Stanford Law School professor Robert Weisberg said prosecutors could ask Cannon to review Brennan’s testimony privately, decide on her own that it wouldn’t incriminate him and order him to answer questions.

Weisberg questioned the government’s approach.

“What the government is doing is rather strange and makes me think: Either they don’t know what they’re doing, or … it could be a Trumpian strategy to just make life as miserable and legally expensive as possible, even in cases you can’t possibly win,” he said.