Bill Barr said that Donald Trump would try to destroy the Republican Party if he were to win the presidency.
In an op-ed in The New York Post, Barr addressed Trump's announcement that he was seeking the Republican Party candidacy for the White House.
It could tear the GOP apart if Trump lost the nomination.
"If the rest of the party doesn't get along with him, he will burn the house down by leading his people out of the GOP," Barr said.
"Trump's willingness to destroy the party if he doesn't get his way is not based on principle, but on his own ego," Barr wrote.
He can't think of a political party as anything but an extension of himself, because of his egoism.
When several of the high profile candidates he'd endorsed in key races were defeated, Trump's status as the GOP's most powerful figure fell.
The Republicans failed to win control of the Senate and only secured a small majority because of the divisive and flawed candidates Trump endorsed.
According to Barr, the GOP's poor performance in the recent elections was due to Trump's antics.
His criticisms are similar to those of Trump's niece, Mary Trump, who thinks that the former president would try to burn everything down if Republicans blamed him for their loss.
The announcement of Trump's candidacy at Mar-a-Lago last week was relatively low key. His opponent, Florida Gov. Ron DeSantis, is gaining in the polls.
Barr was one of the most loyal members of the cabinet. It has been highly critical of Trump over his refusal to concede defeat after the 2020 election and his retention of classified information.
The Republican Party needs new leadership, according to Barr.
"It is painfully clear from his track record in both the 2020 election and the 2022, that Donald Trump is neither capable of forging this winning coalition nor delivering the decisive and durable victory required."
"Indeed, among the current crop of potential nominees, Trump is the person least able to unify the party and the one most likely to lose the general election," he said.