In re Bard IVC Filters Product Liability Litigation


Why It Made the List

Product liability cases are a fact of life with FDA-regulated drugs, devices, and biologics. The product liability system is often called upon to determine whether an individual who has suffered some adverse event, at least allegedly caused by the product, is entitled to compensation from the manufacturer. These cases immediately involve the intersection of the FDA regulatory oversight system and the product liability claims. A constant issue in such litigation is whether the Supremacy Clause[1] preempts such private claims because of the actions and decisions of the Food and Drug Administration (FDA).

Drug and device preemption cases came to the forefront beginning in the 1990s and accelerating in the first part of the 2000s with a series of Supreme Court cases such as Lohr,[2] Riegel,[3] Wyeth,[4] Mensing,[5] and others. Over time, the jurisprudence in this area has continued to evolve as new facts patterns come before courts and judicial analyses continue to evolve.

In re Bard IVC Filters Product Liability Litigation (“Bard”)[6] is one of the latest cases to explore the parameters of preemption. While Bard involves a medical device and so is under a somewhat different legal structure than drugs or biologics, the lessons of Bard apply beyond device litigation.

Bard analyzes the parameters of express preemption, the role of guidance documents as FDA “requirements,” the possible need to include comparative information in product labeling, and procedural requirements for preserving a preemption argument for appeal; all topics of importance to all FDA practitioners—not just litigators.


Factual and Case Background

Bard involves an intervascular filter (IVF), a device that is used to reduce the risk of pulmonary embolisms in patients with blood clots (or potential for blood clots) in their legs. Such clots can break free and travel to the lungs causing serious (potentially fatal) pulmonary embolisms. Some patients cannot take medications (generally “blood thinners”) or such medications are not effective in reducing these risks.

IVFs can be used to treat these patients. An IVF is placed in the inferior vena cava and traps or filters any such blood clots before those clots can get to the heart and then be pumped into the lungs. The filter is anchored into the walls of the blood vessels and are permanent.[7]

In this particular case, Ms. Booker’s physician implanted a Bard Model G2 IVF in Ms. Booker in 2007. Several years later, the filter fractured, and part of the filter perforated her inferior vena cava. Two surgeries were performed to remove the broken filter. While some parts of the IVF were successfully removed, at least one part remains permanently embedded in Ms. Booker’s inferior vena cava.

Over time, thousands of such events are alleged to have occurred and thousands of lawsuits were filed. These cases were combined into one multidistrict litigation (MDL) for certain pretrial purposes. Ms. Booker filed suit against Bard and, as a Georgia resident, asserted design defect and failure to warn claims under Georgia law. One of her claims was that Bard had an obligation to inform the patient (generally via the physician under the learned intermediary doctrine) not only of the risks of the Bard product but also how those risks compare to the risks of competing products.[8]

Bard filed an omnibus motion for summary judgment in the MDL proceedings. In this motion, Bard argued that many of the claims of the various plaintiffs in the MDL litigation were preempted. The District Court disagreed and denied the motion. Ms. Booker’s case was subsequently selected for trial.

At trial, the defendant prevailed on various design claims and on a strict liability failure to warn claim. However, Ms. Booker prevailed on her negligent failure to warn claim and was awarded $1.6 million in compensatory damages and an additional $2 million in punitive damages.[9] Bard appealed.

The Ninth Circuit affirmed the district court on all issues.

Regulatory History of IVF Devices

Medical devices[10] are divided into three, generally risk-based, classes.[11] Class I devices are low risk and usually require no premarket submission.[12] Class II, or moderate risk devices, must demonstrate a reasonable assurance of safety and efficacy under the requirements and processes set forth in 21 U.S.C. § 360c(a) and related provisions. These requirements include, but are not limited to, the satisfaction of “special controls” and a determination of substantial equivalence to a predicate device.[13] Often, these devices are referred to as “510(k)”[14] devices even though these devices are subject to multiple regulatory requirements in addition to the 510(k) substantial equivalence determination. Class III devices are required to go through the “PMA” process as outlined in 21 U.S.C. § 360e.

Initially, IVFs were regulated as Class III devices. In 2000, FDA reclassified these devices as Class II devices and adopted three “special controls”: one dealing with biocompatibility of materials[15]; the second dealing with sterility[16]; and the third relating to IVF submissions including certain “labeling, biocompatibility testing, mechanical testing, sterilization procedures and labeling and clinical data controls.”[17] The Bard IVF at issue in this case (the so-called “G2” model) received FDA clearance in 2005. It was this product that was implanted in Ms. Booker.

Comparative Labeling

The relevant claim for our purposes is plaintiff’s negligent failure to warn claim.[18] The plaintiff asserted that Bard’s labeling was inadequate because the labeling (including the Instructions for Use) did not disclose comparative risks of the Bard IVF compared to other products. The crux of the plaintiff’s argument is that Bard had a duty under Georgia law to inform the user (or physician in this case) of the risks of the Bard product compared to the risks of competitive products. This comparative information, the plaintiff asserts, would have influenced the decision of the physician as to which product to use.

Two legal issues arise from this argument, one directly addressed by the appellate court and the other not.

First, Bard argued that Georgia law did not recognize a duty by the manufacturer to compare or disclose the risks of the manufacturer’s product compared to the risks of competitive products. This is a state law question and, at this stage, does not implicate federal law. The district court found, and the appellate court affirmed, that the adequacy of the warning is a matter for the jury.

Note that in reaching this decision, the court had to find that Georgia law imposes a duty to warn of comparative risks. This is a legal question. If such a duty exists, the adequacy of the actual warning is then a question for the jury.

The Ninth Circuit held that under Georgia law, a manufacturer has a duty to warn of known risks. That duty can extend to a duty to warn the user (or learned intermediary) of comparative risks. Several other federal courts have found such a duty under Georgia law.[19] The court also found no Georgia authority rejecting such a duty. As such, the appellate court utilized what it predicated or believed a Georgia court would conclude. Once a duty to warn of comparative risks is legally recognized, the adequacy of that warning became a fact question for the jury. The court found that there was sufficient evidence to support the jury award.[20]

The second question is whether FDA law permits such a comparative warning absent an FDA-approved label with those comparative claims. In this case, the FDA-cleared label did not include comparative claims, and, to the extent apparent from the public record, Bard never requested such comparative information be added to the labeling[21] or Instructions for Use. This question of FDA law clearly overlaps the preemption issue. If FDA does not permit such comparative information in the labeling, then a state court decision mandating the inclusion of such information would seem to directly conflict with FDA requirements.

The challenge, not explicitly discussed in the appellate court decision, is whether Bard could have added some comparative warning without FDA approval. Generally, FDA is reluctant to permit comparative claims in the absence of head-to-head clinical trials designed to establish the accuracy of such comparative claims.[22] If FDA requirements had prevented Bard from including this comparative information, then permitting a jury to find the warning inadequate could seem to set up an express preemption and a conflict preemption argument.


Bard asserted that Ms. Booker’s claims (and the claims of other plaintiffs in the MDL) were preempted due to the express preemption provisions found at 21 U.S.C. § 360k.[23] Section 360k preempts any state or local requirement (including jury verdicts) that establishes or continues a requirement relating to safety or effectiveness of a device that is “different from, or in addition to,” any FDA requirement. It does not appear that Bard argued conflict preemption or implied preemption.

There is a major difference between preemption for a Class III medical device and preemption for a Class II medical device. Generally there is preemption for a Class III device, except if the plaintiff can assert a “parallel claim.”[24] Conversely, there is generally quite limited preemption for Class II devices. This difference originated in the Supreme Court decision in Lohr when the Supreme Court determined that there was only limited preemption for Class II devices because the then-existing “510(k)” regulatory system did not provide “specific requirements” relating to safety or effectiveness of the device that is needed for express preemption under 360k.[25]

In its preemption analysis in this Class II case, the court primarily relied upon Lohr, the “plain language” or “plain wording” of §360k, and FDA’s regulations interpreting §360k in 21 C.F.R. § 808.[26], [27] In particular, the appellate court focused on the language in §808(d) that “State or local requirements are preempted only when the Food and Drug Administration has established specific counterpart regulations or there are other specific requirements applicable to a particular device under the act . . . ” (emphasis added).

At a high level, the express preemption provision in §360k requires several elements. First, the requirement at issue must relate to safety or effectiveness of the device. That element of §360k is obvious in this case. The entire case revolves around the plaintiff’s claim that the Bard IVF device was not safe (i.e., was defective due to an inadequate warning) and the defendant’s assertion that the device was safe and that plaintiff’s claims to the contrary were preempted.

The second element is that there must be some specific FDA “requirement” that is applicable to the device in question. Under Lohr and §808, these requirements must be specific to the device.[28] The validity of the interpretation set forth in §808 is open to some debate. The “specificity” requirement seems consistent with the plain wording of §360k that state law requirements that are “different” from an FDA requirement are preempted.[29] Logically, there must be some requirement in place before something can be different.

However, the court also ruled that for preemption to apply there must both be a specific requirement and that that specific requirement must apply to the device in question. (In a later section, we discuss whether guidance documents are “requirements” given that guidance documents are not legally binding.)

It is unclear how the specificity requirement in §808 and Lohr and utilized by the court in Bard is consistent with the language of §360k that preempts state requirements that are “in addition to” FDA requirements.[30] A state law requirement is “additive” only if it involves a requirement not already found in FDA requirements. The “addition to” requirement makes it clear that FDA requirements intended to be both the floor and the ceiling. The need for a “ceiling” on requirements is needed to preserve FDA’s role in making benefit/risk decisions and to ensure national uniformity in device design and labeling. By requiring that there be a specific requirement in place before there can be preemption, the court seems to be eliminating the “ceiling” aspect of preemption. If a plaintiff can think of a new requirement, the plaintiff can well argue that there is not an existing specific requirement as mandated by §808(d).

Given the court’s view that a “specific” requirement is needed for preemption, the court focused on this question of whether there are specific FDA requirements applicable to the IVF in question.

The first possible “specific requirement” is the FDA clearance of the Bard G2 IVF itself. This argument failed. Again, under Lohr, the actual “approval” (technically a “clearance”) is not deemed to impose any device-specific requirements. Generally, general requirements do not have preemptive authority under Lohr.

Bard argued that the three special controls set forth in 21 C.F.R. § 870.3375 are the specific requirements needed to trigger preemption as required by §808(d) and Lohr. The court disagreed. In reaching its decision, the court reviewed each special control and assessed whether that special control is applicable not only to the device in question but also to the issues at hand.

The court rejected the first two special controls (a biocompatibility requirement and a sterility requirement) because, in the court’s view, these were not sufficiently specific to this device. As the court said, “[n]either [special control] contains anything specific to intravascular filters, let alone to the particular intravascular filter at issue here.”[31] The court viewed these special controls as akin to the “general” requirements for devices found to be insufficient for preemption in Lohr. What this apparently means is that, at least in the Ninth Circuit, requirements that apply to more than one device type do not meet the requirement for being “specific” to the device. In order to trigger preemption, it seems that FDA would need to revise these biocompatibility and sterility documents into a series of essentially identical documents that name a series of different devices. The value of this is, of course, open to question.

It is interesting that the court focused on whether these two requirements were “specific to” the IVF rather than asking whether these two special controls were relevant to the issues at hand. Neither special control relates to warnings or labeling. Given the focus in §808(d) and in Lohr on the requirement being different, the inapplicability of these two special controls to the case at hand would seem to be an easier pathway for the court.

The third special control[32] does apply explicitly to IVFs. However, the court found that even though this special control specifically applies to IVFs, this special control still failed to meet the preemption test for two reasons. First, this so-called labeling special control was not specific to the Model G2 IVF at issue in this case. Rather, the special control applied to all IVF filters, not just to the Model G2. In reading §808(d), the court determined that the requirement had to be specific (i.e., not a “general requirement”) and that the requirement had to apply to the “particular device.” In this case, the court held that while the specificity element of §808(d) might be satisfied, the applicability of the special control to a “particular device” was not satisfied. The court stated: “[W]e conclude that it [the labeling special control] does not have preemptive effect . . . . [T]he guidance does not impose ‘specific requirements applicable to a particular device,’ . . . such as Bard’s G2 filter. Instead, it applies generally to every member of the class of intravascular filters.”[33]

If the court is correct, it seems that the only special controls that may have preemptive effect are special controls that apply to a specific model of a device. Special controls that apply to all devices within one product category or one “procode” would not seem to have preemptive effect.[34]

The second reason given by the court for not giving preemptive effect to the “labeling” special control is that “the requirements that the intravascular filter guidance imposes are not relevant to Booker’s failure-to-warn claim. State requirements cannot be meaningfully described as ‘different from, or in addition to the specific [FDA] requirements if the two requirements are not relevant to each other.”[35] This argument seems eminently logical if one is focusing on the “different from” prong of §360k. The logic seems strained if one focuses instead on the “in addition to” prong of §360k. Almost definitely, a state law duty or obligation that is “in addition to” an FDA requirement is a duty or obligation not included in the FDA requirements.

In parsing through the court’s decision, it seems that the court has created four categories of requirements for preemption purposes:

  • Truly general requirements or obligations such as the 510(k) clearance process. The court does not give these preemptive effect.
  • Requirements that apply to a product category such as IVF filters. The court did not give these preemptive effect.
  • Requirements that apply to the specific device at issue (not the type of device, but that specific model) but which are not relevant to the issue at hand (thus raising the “different from” issue described above). These are not preemptive under Bard.
  • Requirements that apply to the specific device at issue and which are directly relevant to the issue in the case. These may well be preemptive.

The view that only guidances or other requirement that apply to one model (and it seems only one model) dramatically limits any preemption arguments for Class II devices. Very few special controls are model-specific. Even special controls created as part of the clearance of a specific device under the de novo process are intended to apply to all similar products. The Class II system relies on special controls that apply to a product category or procode.

Are Guidance Documents Requirements?

We next turn to the question of what is a “requirement.” Ms. Booker argued that the special controls for IVFs are not “requirements” under §360k. The plaintiff argued that these “special controls” are actually guidance documents and therefore are not legally binding. This argument is based upon FDA’s own description of the role and effect of guidance documents. Specially, FDA states:

(d) Are you or FDA required to follow a guidance document? (1) No. Guidance documents do not establish legally enforceable rights or responsibilities. They do not legally bind the public or FDA.

(2) You may choose to use an approach other than the one set forth in a guidance document. However, your alternative approach must comply with the relevant statutes and regulations. FDA is willing to discuss an alternative approach with you to ensure that it complies with the relevant statutes and regulations.

(3) Although guidance documents do not legally bind FDA, they represent the agency’s current thinking. Therefore, FDA employees may depart from guidance documents only with appropriate justification and supervisory concurrence.[36]

Guidance documents routinely state at the beginning of the guidance that guidance documents are not legally binding.

Bard argued in response that FDA treats guidance documents as if they are legally binding.

This question gets more complex because, in this case, the actual regulation governing IVFs specifically incorporates guidance documents. The key regulation (21 C.F.R. § 870.3375) specifically lists guidance documents as special controls.

Sec. 870.3375 Cardiovascular intravascular filter.

(a) Identification. A cardiovascular intravascular filter is an implant that is placed in the inferior vena cava for the purpose of preventing pulmonary thromboemboli (blood clots generated in the lower limbs and broken loose into the blood stream) from flowing into the right side of the heart and the pulmonary circulation.

(b) Classification. Class II. The special controls for this device are:

(1) “Use of International Standards Organization’s ISO 10993 ‘Biological Evaluation of Medical Devices Part I: Evaluation and Testing,’” and

(2) FDA’s:

(i) “510(k) Sterility Review Guidance and Revision of 2/12/90 (K90-1)” and

(ii) “Guidance for Cardiovascular Intravascular Filter 510(k) Submissions.”[37]

   So, does the incorporation of a guidance in a product classification regulation make the guidance binding? If so, must FDA follow the Administrative Procedures Act if it modifies or amends the guidance, or can it still use the more abbreviated “Good Guidance Practices” procedures?[38]

The court determined that it did not have to decide any of these questions because the court concluded that the “special controls” set forth above were not specific to the IVF in question.[39]

While the court, unfortunately, did not add clarity to this question, the question remains. For purposes such as preemption, regulatory compliance, labeling, etc., should guidance documents be treated as binding? Does FDA, in fact, treat guidances as mandatory? If a manufacturer violates a guidance, does that create the evidence of negligence or defect for a product liability case? Would allegations of defect based on the failure of the manufacturer to follow a guidance create a “parallel claim” as set forth by Justice Scalia in Riegel? While guidances may not be de jure binding, are they de facto binding?

Hopefully, another case will clarify these and related questions.

Miscellaneous Issues

For the sake of completeness, Bard raises two other, non-FDA specific, issues which should be mentioned.

First, there was a procedure question as to whether the defendant preserved the preemption defense for appeal. Bard did file a motion for summary judgement on preemption in the pretrial MDL proceedings. Bard did not, however, raise preemption in a post-trial motion. Summary judgement orders ordinarily do not quality as “final orders” or “final decisions” ripe for appellate review.[40]

The appellate court, however, followed a line of Ninth Circuit cases holding that an appeal from the denial of a summary judgment motion is appealable if the summary judgement motion involved “purely legal” issues even if there had not been some post trial motion.[41]

Second, Bard also challenged the punitive damages award. The appellate court upheld this award as the evidence was adequate to support the jury decision. Bard’s argument that it could not be found to have acted with “a conscious disregard for the safety of others” (the Georgia standard for awarding punitive damages[42]) because the product was FDA cleared was not successful. Remember that the plaintiff argued (and the jury agreed) that additional and comparative risks should have been disclosed.


Several conclusions are apparent from Bard.

First, despite many statutory changes made after the time period relevant to the Lohr analysis (including a statutory requirement of a reasonable assurance of safety and effectiveness), preemption is a difficult path for defendants in any Class II medical device case. Lohr carries great weight. Perhaps the best preemption argument for a defendant is to identify a specific requirement that would be inconsistent with a jury finding of liability. In essence, conflict preemption may be the best argument for defendants rather than express preemption.[43]

Second, the Bard decision substantially narrows the types of special controls that will be deemed to be “requirements” for preemption purposes. The group of special controls that are applicable for preemption purposes may be so narrow as to be almost never applicable. This line of argument is consistent with the general reluctance of courts to find preemption for Class II devices. Lohr is a tough hurdle for defendants arguing preemption. Bard reinforces this challenge by permitting only a very narrow set of special controls to trigger preemption.

Finally, while the court had the opportunity to opine on whether guidance documents are binding, the court declined to reach that question. Sooner or later, a court will need to face this issue.

*    Leavitt Partners, Professor of Practice, University of Minnesota Law School.

[1]    U.S. Const. Art. VI, cl 2

[2]    Medtronic, Inc. v. Lohr, 518 U.S. 470 (1996).

[3]    Riegel v. Medtronic, Inc. 552 U.S. 312 (2008).

[4]    Wyeth v. Levine, 555 U.S. 555 (2009).

[5]    PLIVA, Inc. v. Mensing, 564 U.S. 604 (2011).

[6]    Booker v. C.R. Bard, Inc., et al., 969 F.3d 1067 (9th Cir. 2020).

[7]    A more detailed description of the use of IVFs can be found at In Re Bard IVC Filters Product Liability Litigation, Booker v. C.R. Bard, Inc., et al., 969 F.3d 1067, 1070–71 (9th Cir. 2020) (Bard).

[8]    Id. at 1072.

[9]    The trial court decision is found at 2018 WL 3037161 (D. Ariz. June 18, 2018).

[10]  IVFs are medical devices under the Federal Food, Drug, and Cosmetic Act (FDCA). 21 U.S.C. § 321(h).

[11]  21 U.S.C. § 360c(a).

[12]  Note that certain Class I devices require premarket submissions under the regulatory structure established for Class II devices, and certain Class II devices must go through the Class III/PMA process. These devices are not relevant for this discussion.

[13]  The substantial equivalence requirement arises under 21 U.S.C. §360(k) (generally referred to as §510(k) of the Food Drug and Cosmetic Act). The substantial equivalence requirement is one of the possible “administrative controls” imposed on Class II devices under 21 U.S.C. §360c(a).

[14]  21 U.S.C. § 360(k).

[15]  21 C.F.R. § 870.3375(b)(1).

[16]  21 C.F.R. § 870.3375(b)(2)(i).

[17]  21 C.F.R. § 870.3375(b)(2)ii.

[18]  The defendant prevailed on various other design and warning claims. As such, these other claims are not part of the appeal.

[19]  Watkins v. Ford Motor Co., 190 F.3d 1213 (11th Cir. 1999); In re Mentor Corp/Obtape Transobturator Sling Prods. Liab. Litig., 711 F. Supp. 2d 1348 (M.D. Ga. 2010).

[20]  Bard, 969 F.3d at 1076–77.

[21]  Labeling is a broad term and includes the label and any other material that “accompanies the product. 21 U.S.C. § 321(m). For our purposes, we will use labeling and Instructions for Use interchangeably.

[22]  See, for example, a 2018 FDA guidance entitled: Medical Product Communications That Are Consistent With the FDA-Required Labeling—Questions and Answers Guidance for Industry. The example at page 21 gives some FDA thinking on the issue of comparative claims (available at

[23]  Note that while there is an express preemption provision applicable to devices, there is no parallel express preemption provision for drugs and biologics. As such, drug preemption cases generally involve implied or conflict preemption, not express preemption. See Wyeth v. Levine, 555 U.S. 555 (2009).

[24]  See Riegel v. Medtronic, Inc. 552 U.S. 312 (2008). The question of what is a “parallel claim” is a complex and oft-litigated issue but is beyond the scope of this chapter. Lohr was based on the 510(k) system as it existed prior to the 1990 Safe Medical Device Amendments (SMDA). The SMDA made major changes and additions to the Class II regulatory oversight system, including requiring an assessment of safety and effectiveness. See, for example, 21 U.S.C. §360c. Despite these statutory changes and commentary such as Ralph H. Hall & Michelle Mercer, Rethinking Lohr: Does “SE” Mean Safe and Effective, Substantially Equivalent, or Both?, 13 Minn. J.L. Sci. & Tech. 737, 747–50 (2012), Lohr remains the general rule for preemption of Class II medical devices.

[25]  See Medtronic, Inc. v. Lohr, 518 U.S. 470 (1996).

[26]  The Court did not apply any “presumption against preemption” as has been argued in other cases. Given that the device in question is a Class II device, the Court focused on Lohr rather than the Class III preemption case of Riegel.

[27]  The Court gave substantial weight to FDA’s interpretation of the Federal Food, Drug, and Cosmetic Act. Bard, 969 F.3d at 1072. The Ninth Circuit seems to have given little or no weight to the statement by the Supreme Court in Riegel that §808 was not of value. Specifically, the Supreme Court stated that FDA’s interpretation “can add nothing to our [preemption] analysis but confusion.” Riegel, 555 U.S. at 329. The appellate court also did not seem to consider the varying interpretations FDA has taken in preemption litigation. In other contexts, differing government interpretations of a statute has resulted in courts giving little or no weight to the agency’s views.

[28]  Bard, 969 F.3d at 1074.

[29]  Remember that the Court asserts that its primary focus is on the “plain wording” of §360k.

[30]  FDA is charged with making complex benefit risk decisions. See, for example, 21 U.S.C. §515e(d)(2). If a state adds new requirements over and above what FDA has deemed appropriate or necessary, that balance can be upset. In addition, if different states can impose additional separate and potentially inconsistent requirements, no manufacturer would be able to see its devices across all fifty states. The preemption provision is intended to thus both preserve FDA’s benefit/risk decisions and also to enable the multistate distribution of devices.

[31]  Bard, 969 F.3d at 1074.

[32]  This special control relates to a number of submission requirements including labeling requirements. See 21 C.F.R. § 870.3375(b)(2)ii.

[33]  Bard, 969 F.3d at 1074.

[34]  FDA has established specific product categories as set forth in 21 C.F.R. §§860–898. This is required by statute. See 21 U.S.C. § 360c(c)–(f).

[35]  Bard, 969 F.3d at 1074–75.

[36]  21 C.F.R. § 10.115(d) (emphasis added).

[37]  21 C.F.R. § 870.3375 (emphasis added).

[38]  21 C.F.R. § 10.115(d).

[39]  Bard, 969 F.3d at 1074.

[40]  28 U.S.C. § 1291 sets forth the requirement that there be a final decision before an appeal is proper. See also, Ortiz v. Jordan, 562 U.S. 180 (2011).

[41]  Banuelos v. Construction Laborers’ Trust Fund for S. Cal., 382 F.3d 897 (9th Cir. 2004); Frank C. Pollara Grp., LLC v Ocean View Inv. Holding, LLC, 784 F. 3d 177 (3d Cir. 2015).

[42]  Zeigler v. CloWhite Co., 507 S.E.2d 182 (1998).

[43]  The differences between these two may be nuanced. The ability to identify a specific FDA requirement that is contrary to the jury finding is one way to consider conflict preemption.