Alan Dershowitz said Special Counsel Robert Mueller was "really foolish" not to seek warrants for the tens of thousands of emails he obtained from the Trump transition team.
Mueller's investigators acquired the emails from the General Services Administration (GSA). A lawyer for the Trump transition trustee claimed the move was "unauthorized," and that the materials are private and privileged.
"Why not seek the warrant?" Dershowitz said on "America's Newsroom" on Monday. "Getting warrants is like getting candy at Christmas. It's very easy to get. And not getting a warrant gives the defense an opportunity to challenge it in court."
He said it's a close question and he could see a court ruling for either side, but it was a mistake for Mueller not to take the precautionary step of getting a warrant.
Dershowitz, a Harvard Law professor emeritus and lifelong Democrat, said Mueller has been conducting a "sloppy investigation" and he now has a credibility problem, which "plays into Trump's hands."
He said Mueller should have been more careful about which investigators he brought on his team, he should have immediately disclosed that FBI counterintelligence officer Peter Strzok was removed from the Russia probe over his anti-Trump text messages and he should reveal if the infamous Trump dossier was used to obtain clearance for surveillance on Trump associates.
"When you're going after the president, you have to be Caesar's wife, you have to be above reproach. You can't give the other side any ammunition, and he has given the other side plenty of ammunition," Dershowitz said.
Watch his full analysis above and see Judge Napolitano's view, here.