Criminal Justice & the Rule of Law Executive Branch

Trump’s Fourth Amendment Claims and the Strategy Behind the Challenge to the Mar-a-Lago Search

Matthew Tokson
Wednesday, September 7, 2022, 10:47 AM

Trump’s challenge to the Mar-a-Lago search is based largely on Fourth Amendment claims. Those claims are unusual, interesting, ultimately meritless, and likely driven by strategic interests having little to do with constitutional law.

Former President Trump in 2016. (Gage Skidmore,; CC BY-SA 2.0,

Published by The Lawfare Institute
in Cooperation With

Editor’s Note: An earlier, shorter version of this piece was originally posted on 

Following the FBI search of former President Trump’s Florida estate, most attention has focused on Trump’s call for a special master to review the seized documents. Trump filed a complaint in federal court asking for the appointment of an external party to review each of the documents to filter out those that implicate executive or attorney-client privilege. Judge Aileen Cannon, a Trump appointee, granted this request on Monday morning and enjoined the Justice Department from further reviewing any seized documents. At the least, Trump has succeeded in delaying the investigation and obtaining a thorough privilege review.

Ultimately, however, Trump’s complaint is largely premised on Fourth Amendment claims rather than privilege claims. What are those claims? And what are the strategic reasons why Trump is raising them in the first place? While his attorneys have been criticized as inept, they raise some fairly novel Fourth Amendment arguments worthy of attention. If successful, these claims could lead to the return of seized documents to Trump or the suppression of all of the documents in a subsequent prosecution. And whatever the weaknesses of the attorneys’ arguments, their approach is well-suited to serve broader strategic goals. Ultimately, a central purpose of the litigation appears to be obtaining “an unredacted copy” of the affidavit that provided support for the search warrant. That affidavit could reveal the Justice Department’s sources of information inside of Trump’s organization and Mar-a-Lago, and its disclosure may compromise the government’s ongoing criminal investigation. 

The Breadth of the Search Warrant 

Trump’s complaint begins with a Fourth Amendment claim. He argues that the search warrant obtained by the FBI for his estate was “facially overbroad” under the Fourth Amendment. Trump notes that the warrant permitted the seizure of, among other things,

Any physical documents with classification markings, along with any containers/boxes … in which such documents are located, as well as any other containers/boxes that are collectively stored or found together with the aforementioned documents and containers/boxes. (Emphasis added.)

In other words, if agents found a classified document, they could seize the box that it was located in, plus any boxes stored along with that box. Trump objects to this last part, arguing that it makes the warrant too broad. Trump argues that the FBI’s probe should be limited to only those boxes containing obviously classified documents. 

The specificity of search warrants is frequently litigated for several reasons. The particularity requirement—which protects the rights of individuals from unreasonable searches and seizures—is generally not rigorous, and countless courts have noted that it must be applied with a “practical margin of flexibility.” For example, in a complex investigation, extensive searches may reasonably be conducted in order to piece together the “puzzle” of criminal activity. And even sweeping statements in a warrant are generally not invalidated as overbroad. Instead they are typically construed to allow the seizure of any documents relating to the crimes listed in the warrant. 

Ultimately, the merits of Trump’s overbreadth claim come down to one question: Was there probable cause to believe that evidence of the suspected crimes would be found in boxes adjacent to boxes containing obviously classified documents? It’s very likely that there would be. First, the Justice Department reported that it found 48 empty folders marked “classified,” indicating there could be 48 loose classified documents floating around in Trump’s stored materials. It’s reasonably probable that some of these documents would be found in boxes adjacent to boxes containing the empty folders. This is especially so in light of the particular facts of the document storage at Mar-a-Lago, where “documents marked as classified were stored haphazardly, mixed with everyday items.” 

Second, the Justice Department does not need to prove that there was probable cause to believe that classified documents would be found in adjacent boxes. It only needs probable cause to believe that any government or presidential records that are evidence of the suspected crimes would be found in those boxes. For example, one of the suspected crimes was 18 U.S.C. § 2071—the willful concealment, removal, or mutilation of any government property. Any government document not belonging to Trump found at Mar-a-Lago would be evidence of this crime, and there is very likely probable cause to believe that a box stored adjacent to a box of classified government records would contain additional government records. 

Even if the warrant is ultimately determined to be overbroad, persons searched pursuant to a seemingly valid warrant can generally obtain no relief. The Supreme Court has instituted the “good-faith exception,” which establishes that the government may introduce unlawfully obtained evidence if the police relied in good faith on legal authority such as a warrant or statute. So long as a warrant is not obviously facially deficient, police reliance on it will be deemed reasonable and thus the evidence will be introduced in court. A similar standard applies to claims like those contemplated by Trump, who states that he plans to file a motion for the return of unlawfully seized evidence under Federal Rule of Criminal Procedure 41(g). That rule was amended in 1989 to allow the United States to retain evidence seized in good-faith reliance on a warrant. And the warrant at issue here was not obviously facially deficient—on the contrary, it would be shocking if a judge were to find it invalid. Even if Trump were to prevail on his overbreadth claim, he would have no remedy. 

The Mere Evidence Rule

Trump makes a few additional Fourth Amendment arguments. In passing, his brief invokes an old, long-since-overturned Fourth Amendment doctrine known as the “mere evidence rule.” This rule once prohibited the police from seizing evidence that was not contraband, an instrumentality of the crime, or fruits of the crime itself. Created in the 1886 case Boyd v. United States, it was formally abandoned in the 1967 case Warden v. Hayden, following decades of general disuse. Trump attempts to rely on this defunct doctrine, raising the essentially frivolous argument that “boxes of personal documents, photographs, and items such as clothing are by definition not contraband and thus may not be lawfully seized.” The court is likely to have little appetite for reviving this long-dead rule, which, among other things, would prohibit the police from obtaining search warrants for evidence of murders. There’s no legal problem with the police seizing “mere evidence” under a warrant. And personal items intermingled with classified documents may be useful evidence of record mishandling because they establish who took the documents and how they’ve been handled.

The Search Warrant Affidavit

Trump raises several vague questions about the validity of the search warrant and its underlying affidavit. His complaint suggests that the affidavit was probably riddled with material omissions and/or false statements. Presumably, he could verify these accusations only if he were allowed to see the affidavit itself. Indeed, he later requests the full affidavit, arguing that it “is the only way to ensure the President can properly evaluate and avail himself” of his constitutional protections. Specifically, Trump has indicated that he plans to file a motion under Federal Rule of Criminal Procedure 41(g) for the return of personal property seized by the government, on the grounds that the search of Mar-a-Lago was unconstitutional. In order to support this hypothetical future motion, Trump asks for access to the unredacted affidavit.

This raises an interesting question: How long can the government withhold an affidavit from the subject of an investigation who wishes to examine it and potentially challenge a warranted search? Generally, affidavits are rarely disclosed before the government files charges, as doing so may compromise “the integrity and security of an ongoing criminal investigation.” Here, the case for delaying the disclosure of the affidavit while the criminal investigation continues is strong. The unredacted affidavit would reveal the identities of several witnesses who could be subject to potential intimidation or retaliation. It also includes information about investigative techniques that could provide a road map of ways for the Trump team to obstruct the Justice Department’s investigation—which is especially important given that the warrant found probable cause for obstruction of justice. Finally, the unredacted affidavit would disclose the names of the law enforcement official or officials who applied for the warrant. This divulgence of those officials’ names would likely place them in danger, much like the FBI agents who were publicly identified to have carried out the initial search of Trump’s residence and who received repeated threats of violence. For these reasons, no judge is likely to order the Justice Department to disclose the unredacted affidavit at this early stage of the investigation.

The Special Master Revisited

Trump’s filings reveal the central strategic importance of obtaining an unredacted affidavit. His team also sees the appointment of a special master, nominally concerned with matters of privilege, as a means for obtaining the unredacted affidavit. The brief in Trump’s initial filing, after discussing the hypothetical possibilities for omissions or lies in the affidavit, pivots to a discussion of the special master, arguing that the “appointment of a Special Master with a fair-minded approach to providing defense counsel with information needed to support any Rule 41(g) filing is an appropriate use of the Court’s authority.” This appears to suggest that the special master should provide Trump’s attorneys with access to the affidavit in order to support their Rule 41(g) motion claiming an unconstitutional search. Yet providing Trump’s attorneys with investigative documents is far beyond the traditional function of a special master, who typically reviews seized documents for privilege and keeps privileged documents separate from those reviewed by authorities. 

Trump’s reply brief is even clearer in its attempt to use the special master as a means to obtain the unredacted affidavit. Buried deep in a discussion of the special master’s review procedures, the brief requests that the government provide to the special master and to Trump “a copy of the Search Warrant, and an unredacted copy of the underlying application materials,” which include the affidavit revealing the witnesses and sources of information that supported the warrant. Again, such materials have essentially nothing to do with the special master’s duties of sorting privileged and unprivileged materials. Rather, Trump’s attorneys are attempting to use the court’s likely appointment of a special master as a means of obtaining unrelated, sensitive investigative materials that could potentially be used for intimidation or obstruction

Cannon’s order granting Trump’s request for a special master leaves this issue for later, directing the parties to confer on the special master’s duties and powers and to identify any areas of disagreement. She will presumably rule on this issue following the parties’ filing on Sept. 9. She also expressly reserves ruling on Trump’s (not-yet-officially-filed) request for the return of property under Rule 41(g), pending further review. That will apparently involve “comprehensive review of the seized property” by the special master to determine whether the personal items seized have evidentiary value. Cannon’s opinion gives little indication which way she will rule on the affidavit issue, although it does at one point discuss a potential indictment of Trump as an irreparable harm that weighs heavily in Trump’s favor on an equitable balancing, especially “[a]s a function of Plaintiff’s former position as President of the United States.” In addition, Cannon twice granted Trump more relief than he requested. Trump’s complaint asked for an injunction against the Justice Department’s review of the seized materials pending the appointment of a special master, but Cannon enjoined the criminal investigation until the special master completes the review process. In addition, Trump’s reply brief clearly states that he “has not yet filed a Rule 41(g) motion” but Cannon directed the special master to make findings on the potential return of Trump’s property under Rule 41(g). It’s also possible that Cannon’s rapid and thorough accessions to Trump’s unusual requests thus far indicate that she will push the envelope even further and command the Justice Department to disclose the unredacted affidavit. But that extreme step is still unlikely.

It is currently unknown whether Trump’s attorneys’ creative attempts to obtain the unredacted affidavit will be successful. But regardless of how the court ultimately rules on that issue, Trump’s underlying Fourth Amendment arguments are weak, and the likelihood that he’ll succeed in getting the bulk of the documents back is extremely low. Trump may have various strategic reasons for filing this motion, but when it comes to the Fourth Amendment, Trump appears to be headed for a loss.

Matthew Tokson is a Professor of Law at the University of Utah S.J. Quinney College of Law, writing on the Fourth Amendment and other topics in criminal law and procedure. He is also an affiliate scholar with Northeastern University's Center for Law, Innovation and Creativity. He previously served as a law clerk to the Honorable Ruth Bader Ginsburg and to the Honorable David H. Souter of the United States Supreme Court, and as a senior litigation associate in the criminal investigations group of WilmerHale, in Washington, D.C.

Subscribe to Lawfare