Kamala Harris was left aghast when President Joe Biden donned a “Trump 2024” cap at a Pennsylvania firehouse in a bizarre scene at the height of last year’s presidential race, a bombshell new book has revealed. During a visit to a Shanksville firehouse while commemorating the 23rd anniversary of the 9/11 attacks, Biden, now 82, posed with more than a dozen youngsters clad in pro-Trump attire — then briefly put on the cap after being egged on by a member of the crowd. “I need that hat,” Biden had told an audience member of the pro-Trump merch, according to the new book “Original Sin,” co-authored by Jake Tapper and Alex Thompson.Biden had at first refused when an audience member exhorted, “Put it on!” saying, “I ain’t going that far” — only to then plop the hat directly on top of his Station 627 hat honoring the volunteer fire company. “What is he doing?” Harris — by that point the Democratic nominee after Biden ended his re-election bid July 21 — asked her advisers, per Tapper and Thompson. “This is completely unhelpful,” the veep added. “And so unnecessary.”The Trump campaign seized the viral hat moment to indicate that Biden was actually supporting Trump, and had had enough of Harris. “Thanks for the support, Joe!” the Republican campaign wrote on social media alongisde an image of Biden smiling in the hat. At that point, the Democratic campaign decided to stop holding any public events with Biden before the Nov. 5 election — but the president’s unpopular, gaffe-laden presence continued to loom over the campaign.According to Tapper and Thompson, Harris advisers adopted “gallows humor” about Biden’s many missteps — such as when he told party loyalists at a New Hampshire campaign office Oct. 22 that “we gotta lock him up” in reference to the former president and then-Republican nominee Meanwhile, the authors report, Biden “had seen [Bill] Clinton and [Barack] Obama and others out on the campaign trail and wanted to be out there too. He didn’t seem to understand what a liability he had become.” Biden’s last negative contribution to the Harris campaign came Oct. 29, when he responded to comedian Tony Hinchcliffe calling Puerto Rico a “floating island of garbage” during a Trump rally at Madison Square Garden two days earlier.Biden calling Trump supporters “garbage” infuriated Republicans — but the controversy got worse when the White House Communications Office claimed Biden had actually meant his “supporter’s” — referring to Hinchcliffe — editing the official transcript in the process. “What are we going to do about this?” Harris asked at that point in apparent exasperation, per the book. “Original Sin” is available now. #news #politics