What do Russia’s incursion into Ukraine, the hacking of Sony, and democratic instability in Venezuela have in common? The U.S. response to each has been economic sanctions. In the twenty-first century, economic sanctions are perhaps the most frequently used tool in the U.S. foreign policy toolbox because they can inflict pain without having to resort to the use of kinetic force.

But this increasing reliance on sanctions has created a new legal problem. Does freezing assets without a warrant—which sounds a lot like “seizure”—violate the Fourth Amendment? Historically, this issue was not a problem because economic sanctions were targeted entirely against foreign countries—entities that do not enjoy Fourth Amendment protection. In today’s complex financial landscape, however, the issue is not so simple. Many financial transactions subject to U.S. sanctions involve parties protected, or at least arguably protected, by the Fourth Amendment.

To date, courts have reached a number of different conclusions about whether the Treasury Department should be required to obtain a warrant when it freezes assets. Some courts have held that the Fourth Amendment simply does not apply, or that it applies but a special needs exception precludes a warrant. Other courts have held that a warrant is generally required or that, based on the facts of the case, a warrant is required in that instance. This Note proposes a new fact-specific “reasonableness” test to evaluate whether the Treasury Department should be required to get a warrant before freezing assets.