What about attorney-client privilege? How the FBI can obtain a warrant for Cohen's office

William Cummings | USA TODAY

Show Caption Hide Caption FBI agents raid offices of Trump lawyer Michael Cohen Federal investigators associated with the FBI and the Mueller investigation have raided the offices of President Trump's personal lawyer Michael Cohen and seized communications between Cohen and his clients.

The news that the FBI raided the offices of President Trump's personal attorney Michael Cohen Monday caused many people to wonder how such a raid could be justified given the protections afforded under attorney-client privilege.

"If by raiding the office of @realDonaldTrump's attorney, the @fbi violated Trump's attorney-client privilege, this is about to get really ugly," tweeted conservative Fox News host Laura Ingraham.

And the president himself tweeted Tuesday morning, "Attorney-client privilege is dead!"

But former U.S. attorney and deputy assistant attorney general Harry Litman said the way the FBI handled the raid actually showed the seriousness with which the Department of Justice treats material that might be protected by attorney-client privilege.

"It’s very unusual for the Department of Justice to permit prosecutors to raid an attorney’s office and that’s because you want to be careful not to get privileged material," said Litman, who teaches at the UCLA School of Law and continues to practice at the law firm Constantine Cannon.

More: Donald Trump again rants against Robert Mueller and a 'witch hunt'

If by raiding the office of @realDonaldTrump’s attorney, the @fbi violated Trump’s attorney-client privilege, this is about to get really ugly. — Laura Ingraham (@IngrahamAngle) April 9, 2018

Attorney–client privilege is dead! — Donald J. Trump (@realDonaldTrump) April 10, 2018

In order to get the OK to raid Cohen's office, prosecutors would have had to get approval from high up — in this case from Deputy Attorney General Rod Rosenstein — and demonstrate to a federal magistrate both probable cause and the need for a warrant instead of a subpoena (such as a concern that Cohen might destroy evidence), Litman explained.

In addition, the probable cause would have to relate to a crime centered on Cohen, not Trump or someone else. "You can’t use it as end run around to get to the client," Litman said.

There will also be a "taint team" to examine everything before it is handed over to prosecutors to make sure that those conducting the case never see any material that might be "tainted" by attorney-client privilege.

The only way the prosecution would be permitted to examine any material that might otherwise fall under the attorney-client umbrella is if it is determined to be part of a crime jointly undertaken by the attorney and the client. But for the privilege to be nullified under the "crime-fraud exception," Litman said the taint team would have to get the approval of the court before the material could be presented to the prosecution.

In order to fall under attorney-client protection, the documents just have to be related to Cohen dispensing legal advice or gathering information in order to give that advice, Litman said. But merely having an attorney involved does not guarantee the protection.

"It can’t just be that somebody with the bar degree is in the general vicinity," Litman said.

Based on his experience with cases involving issues of attorney-client privilege, Litman said is likely that the prosecution never sees 80% or more of the documents.

Another reason raids on attorney's offices are rare is that they can easily come back to haunt the prosecution.

"If you go to the attorney’s office and you look at attorney-client privileged material by mistake, you’re in a world of hurt," Litman said. "You’re going to get disqualified from the whole matter and the whole prosecution could go down the tubes."

And if the potentially privileged material is challenged, the burden of proof is on the prosecutors to show that they made "zero use of privileged material" and their investigation was not in any way influenced by it.

"Then, if you lose that fight, it's quite possible that anybody who's seen that document is off the case," Litman said. "So, you’re playing with fire."

More: Stormy Daniels accuses Trump lawyer Michael Cohen of defamation

Opinion: Stormy Daniels takes on Donald Trump, but lawyer Michael Cohen is the clear loser