Chris Christie unleashed an epic Twitter takedown of Donald Trump’s White House hiring practices after the former president bragged about bringing on “the best” staff. “It’s plain and simple: Either Donald Trump doesn’t know how to pick personnel, or he’s the worst manager in the history of the American presidency,” Mr Christie, who is vying for the Republican presidential nomination against Trump, tweeted on Monday. The former New Jersey governor followed that tweet with nine more, comparing what Mr Trump said about White House appointees before he hired them and after his eventual falling out with them. In the tweets, Mr Christie noted that Mr Trump called Chairman of Joint Chiefs of Staff Gen. Mark Milley a “great patriot” and a “great soldier” before calling him a “f***ing idiot” and that he called former Secretary of Defense James Mattis “the closest thing to General George Patton that we have” before he called him “the world’s most overrated general.” There are plenty more examples. Former Attorney General Bill Barr was Mr Trump’s “first choice from day one” before he was “gutless” and a “coward.” Former Secretary of State Rex Tillerson had a “deep understanding of geopolitics” before Mr Trump called him “dumb as a rock.” Former Chief of Staff Mick Mulvaney was doing an “outstanding job” before Mr Trump called him a “born loser.” It’s a record that undercuts Mr Trump’s frequent boast that he hires the “best people.” A number of the people he hired for his administration are not supporting his second run for president, in some cases criticising his judgment in personal terms. Two members of his administration, former vice president Mike Pence and former secretary to the United Nations Nikki Haley, are running against Mr Trump. “Republicans should listen to what he says,” Mr Christie said in an interview with CNN’s Jake Tapper on Monday. “He’s a petulant child when someone disagrees with him.” Mr Christie, who is polling in the low single digits and has not held elected office since leaving the governor’s mansion in New Jersey more than five years ago, has distinguished himself apart in the crowded Republican primary as the only candidate willing to repeatedly and harshly criticise Mr Trump. The irony, of course, is that Mr Christie cozied up to Mr Trump after Mr Trump’s triumph in the 2016 presidential nominating contest. Mr Christie served as an adviser to Mr Trump throughout the 2016 general election campaign and led his presidential transition team. He remained a close ally of Mr Trump’s throughout his presidency, turning on him only after the Capitol riot of January 6. Mr Christie announced his second bid for the presidency earlier this month. He last won an election in 2013, four years before he left office in New Jersey with one of the lowest approval ratings ever recorded for a governor. Read More Trump news – live: Judge sets Mar-a-Lago classified papers trial date as Hunter Biden reaches plea deal Trump faces questions about whether he'll drag down the Republican Party after his indictments Chris Christie slams GOP debate pledge as a ‘useless idea’ and rips ‘loser’ Trump Miami's Francis Suarez looks to become first sitting mayor to be president