William Barr says working with Trump sometimes felt like 'Groundhog Day,' with advisors taking turns on who would 'eat the grenade'

• Former AG William Barr said working for Trump sometimes felt like "Groundhog Day."
• Barr says Trump had a lot of ideas, though many were "bad" and "legally problematic."
• Barr describes pushing back on Trump's ideas in his new memoir released Tuesday.

Working for President Donald Trump sometimes felt like "Groundhog Day," former Attorney General William Barr writes in his new book, "One Damn Thing After Another: Memoirs of an Attorney General."

Barr describes his ex-boss as a "hyperactive generator of ideas." But many of those ideas were "bad" and "legally problematic," which would lead Barr and former White House counsel Pat Cipollone to take turns on pushing back on Trump.

"We operated like a tag team, so that neither of us would provoke too much of the President's ire at one time," Barr writes. "We referred to this as choosing who would 'eat the grenade.'"

One such idea that Barr had to "eat the grenade" on was Trump's proposal of an executive order to end birthright citizenship for American-born children to parents who are noncitizens or  undocumented immigrants.

"This required reinterpreting the Fourteenth Amendment's standard for citizenship and raised a host of legal and practical problems," Barr writes. "Even if the Constitution allowed Congress to do this, trying to do this unilaterally by executive order instead of statute was essentially a suicide mission."

Barr writes that he and other legal advisors would have to talk Trump out of whichever problematic idea he floated, but there were issues that the former president would "raise relentlessly no matter how many times the legal problems were explained."

Barr called these issues "Groundhog Day" issues, referencing the 1993 film starring Bill Murray in which he relives the same day, February 2, over and over again.

"Working for Trump could feel like that sometimes. He would raise the same issue again and again at regular intervals. You would think the matter was settled and decided, but then he would bring it up again as though it wasn't. We would discuss it again, and it seemed he was satisfied. Then two weeks later, he'd bring it up again. On some issues, February 3 just wouldn't come," Barr writes.

Barr's new book has prompted criticism from Trump.

"I would imagine that if the book is anything like him, it will be long, slow, and very boring," Trump wrote in a letter to NBC News' Lester Holt last week.