WASHINGTON — President Donald Trump gave embattled GOP Senate candidate Roy Moore a vigorous formal endorsement Monday, looking past allegations of sexual misconduct with Alabama teenagers as Republican leaders in Washington, once appalled by Moore's candidacy, began to come to grips with the ever-clearer possibility of his victory. Buoyed by the taste of his own success in Congress as the Republican tax bill inches closer to passage, Trump telephoned Moore to offer encouragement as well as support and also argued in a pair of tweets that Moore's vote was badly needed to push the president's policies forward. In addition, Senate Majority Leader Mitch McConnell, who was initially among several national Republicans to urge Moore to drop out of the race, said Sunday it was up to Alabama voters to decide whether the former state Supreme Court chief justice should be elected. Weeks ago, when accusations of sexual misconduct with teenagers first surfaced, Trump's spokesman had said the president believed Moore would "do the right thing and step aside" if the allegations were true. Top Republicans vowed to expel him from the Senate if he won his Dec. 12 special election. And, publicly and privately, GOP leaders described the allegations against Moore as credible and insisted there were no circumstances under which he should serve in the Senate. Trump's tweets on Monday showed his thinking has evolved as Moore has rejected his party's appeals and doggedly remained in the race. In the phone call, Moore said, Trump offered "his full support and said he needs a fighter to help him in the US Senate." Moore tweeted that the president told him: "Go get 'em, Roy!" Trump's move was somewhat symbolic: He had already all but endorsed Moore, repeatedly criticizing Democratic rival Doug Jones on Twitter and planning a campaign-style rally in Pensacola, Florida, on Friday, less than 20 miles from the Alabama border and just four days before voters head to the polls. Still, Trump's decision to do away with any pretense of distance made clear he is increasingly confident in Moore's chances of victory despite the continued unease of some other Republican leaders. A Moore victory would