Boasberg is also well-known among Trump allies for his role as a judge on the secretive Foreign Intelligence Surveillance Court during the period when the FBI was investigating whether Trump's successful 2016 campaign had colluded with Russia to tip the outcome of the election.

The U.S. judge who temporarily blocked President Donald Trump’s administration from invoking wartime powers to deport migrants has for years handled high-stakes cases involving sensitive security or political issues - sometimes ruling in Trump's favor.