Mr Blanche risks destroying the career he upended for Mr Trump if the former president is convicted.
Last year, he left a job In Manhattan’s oldest legal firm to represent him, taking on his second-ever defence case as a criminal lawyer. He also abandoned the Democratic party to join the Republicans.
But on Thursday he proved his naysayers wrong, transforming from a soft-spoken lawyer to Mr Trump’s attack dog as he harried Cohen, the president’s former “fixer” turned star prosecution witness.
Cohen claimed he phoned Mr Trump, via his bodyguard, in Oct 2016 to say he had made a hush money payment to a porn star with whom his boss allegedly had an affair.
However, Mr Blanche noted that he had texted the bodyguard immediately before and after the call about prank calls he had been receiving from a 14-year-old.
This was what the 96-second call was about, he said – not Cohen setting out how he had paid off Stormy Daniels, an adult film star. “That was a lie,” he virtually shouted at the witness.
Sabrina Shroff, a New York defence lawyer who repeatedly crossed swords with Mr Blanche when he was a prosecutor, said he had always had the same “killer instinct” as his colleagues in the city’s southern district.
“He was just as aggressive, just as ambitious and just as determined to win as any other person in the office then, or in the office now,” she told The Telegraph.
“At the end of the day, he wanted that conviction just like everybody else in that office. He just happened to be soft-spoken. That’s it.”
She added: “At least he’s standing up to defend something that he believes in, as opposed to working at some white shoe law firm just making money – so good for him.”