The Fourth Amendment Has No “Defensive Search” Exception

​U.S. intelligence agencies justify tens of thousands of warrantless backdoor searches of Americans’ communications by claiming an exception to the Fourth Amendment for “defensive” purposes.
 
In testimony to Congress, FBI Director Christopher Wray has said that such defensive searches are absolutely necessary to protect Americans in real time who may be potential victims of foreign intelligence agents or cyberattacks. On this basis, the FBI and other agencies every year conduct tens of thousands of warrantless “backdoor” searches of Americans’ communications with data extracted from programs authorized by FISA Section 702 – even though this program was enacted by Congress not to spy on Americans, but to authorize U.S. agencies to surveil foreign spies and terrorists located abroad.
 
Noah Chauvin, Assistant Professor of Law at Widener University School of Law, in a 53-page paper neatly removes every leg of the government’s argument. He begins with the simple observation that there is no “defensive” exception in the Fourth Amendment. Indeed, an analogous claimed exception for “community caretaking” was rejected by the U.S. Supreme Court in the 2021 decision on Caniglia v. Strom, holding that the government could not enter a home without a warrant based on the simple, non-exigent claim that the police needed to check on the homeowner’s well-being. Whether for community caretaking or for surveillance, the “we are doing this for your own good” excuse does not override the Fourth Amendment.
 
In surveillance, the lack of constitutional validity makes the government’s position “a political argument, not a legal one.” Chauvin adds: “It would be perverse to strip crime victims of the Fourth Amendment’s privacy protections – a person should not lose rights because they have been violated.”
 
It is apparently on the basis of such a “defensive search,” for example, that the FBI violated the Fourth Amendment rights of Rep. Darin LaHood (R-Ill). In that case, the FBI was concerned that Rep. LaHood was being unknowingly targeted by a foreign power. If the FBI can secretly violate the rights of a prominent and respected Member of Congress, imagine how blithely it violates your rights.
 
While making these sweeping claims of violating the Fourth Amendment to protect Americans, “the government has provided almost no public information about how these defensive backdoor searches work.” Chauvin adds: “The government has claimed it uses backdoor searches to identify victims of cyberattacks and foreign influence campaigns, but has not explained how it does so, saying only that backdoor searches have ‘contributed to’ or ‘played an important role in’ intelligence services.”
 
Also unexplained is how the government identifies potential American victims, or why it searches for victims instead of potential perpetrators. Nor does it reveal its success rate at identifying potential victims and how that compares to traditional methods of investigation. Finally, Chauvin asks: “Would obtaining permission before querying a victim compromise the investigation?”
 
It is a matter of settled law that any American can give informed consent to waive his or her Fourth Amendment rights. “It seems particularly likely,” Chauvin writes, “that would-be victims will grant the government permission to perform defensive backdoor searches.” One can easily imagine a long list of companies – from hospitals to cloud providers – that would grant such blanket permission.
 
So why not just do that?
 
Finally, Chauvin appeals to Congress not just to remedy this backdoor search loophole for Section 702. He proposes closing this loophole for Americans’ digital data that U.S. intelligence and law enforcement agencies purchase from third-party data brokers, as well as for Executive Order 12333, a non-statutory surveillance authority claimed by the executive branch.
 
At the very least, Congress should demand answers to Chauvin’s questions about how defensive searches are used and how they work. He concludes, “the government’s policy preferences should never override Americans’ constitutional rights.”