WASHINGTON (AP) — Despite President-elect Joe Biden's victory, Senate Majority Leader Mitch McConnell said Monday President Donald Trump is “100% within his rights” to question election results, as GOP lawmakers fall in line behind the White House.

The Republican leader's remarks, his first public comments since Biden was declared the winner of the presidential election, show how reluctant Trump's allies on Capitol Hill have been to defy the president, even in his defeat.

Most Republicans are refusing to congratulate Biden or declining to push Trump to accept the outcome, even though there is no evidence of widespread voter fraud.

“Our institutions are actually built for this,” McConnell said as he opened the Senate. “We have the system in place to consider concerns and President Trump is 100% within his rights to look into allegations of irregularities and weigh his legal options.”

McConnell said the process will play out and “reach its conclusion.”

Republicans are closing the Trump era much the way they started it, by joining the president in shattering civic norms and sowing uncertainty in institutions, now in a way that threatens the nation's normal transition of power.

Privately, Republicans on Capitol Hill say they are in a tough spot, wary of crossing Trump and his most ardent supporters. But their actions are casting doubt on the durability of the nation's elections system and impeding Biden's new administration. The head of the General Services Administration under Trump has held off on formally beginning the Biden transition to the White House.

Trump has declined to concede the presidential race and is mounting legal fights in several states, but there has been no indication or evidence of voter irregularities or widespread fraud in the election.

The president's refusal to accept the results means the election disputes could drag for weeks as states certify their tallies or push to mid-December, when the Electoral College is set to vote.

Sen. Lindsey Graham, R-S.C., said he would encourage the president “not to concede.”

With the Senate majority on the line, Republicans don’t dare risk alienating Trump or his supporters ahead of Biden's Jan. 20 inauguration.

In Georgia, where Trump is teetering, both Republican senators are being forced into a Jan. 5 runoff that will determine party control. Sens. David Perdue and Kelly Loeffler jointly called the their state’s election system an “embarrassment.”

Many Republicans have signaled a December deadline, pointing to the time it took to resolve the disputed 2000 race before Democrat Al Gore conceded to Republican George W. Bush.

McConnell spoke shortly after meeting with Attorney General William Barr at the Capitol. Barr has authorized federal prosecutors across the U.S. to pursue “substantial allegations” of voting irregularities, according to a memo to U.S. attorneys obtained by The Associated Press.

“In the end, we want all legal ballots to be counted,” the No. 2 House Republican, Steve Scalise, told AP. “You go back to Bush v. Gore, it was second week of December that it got resolved ... so there’s still questions out there that need to get resolved and that process is playing itself out."

Unlike the 2000 election, when a few hundred votes in Florida separated Bush and Gore, Trump is casting a wide net of legal challenges in states where Biden is thousands of votes ahead of him.

Some Republicans scoff at the president's legal team, helmed by personal attorney Rudy Giuliani, and doubt the president has a credible route to challenge the election results. Election officials from both political parties have publicly stated the election went well.

Senate Democratic leader Chuck Schumer said Monday the Republicans’ refusal to stand by the election results is “extremely dangerous, extremely poisonous to our democracy.”

Schumer said election lawsuits can be valid but they must be based in evidence and facts. He dismissed Trump's challenges as “frivolous.”

“Joe Biden won the election fair and square,” Schumer said.

McConnell and Republicans said Monday they don't want the “media” to declare the outcome of the election.

But actually, the results in the presidential election are being determined much they way they are in all elections — including those for the House and Senate that are not being questioned — based on an analysis of vote tallies.

McConnell touted the results Monday of the congressional races — GOP senators brushed back Democratic challengers and House Republicans expanded their ranks — even as he raised questions about the presidential contest.

“Let’s not have any lectures, no lectures, about how the president should immediately, cheerfully accept preliminary election results,” McConnell said.

Pressed if there was any evidence of voter fraud, GOP Sen. John Cornyn, who just won reelection in Texas, demurred.

“That’s really not my, my role,” Cornyn told reporters on Capitol Hill. “There is a process that is available, and I don’t begrudge the president for availing himself of that process — but in the end, they’re going to have to come up with some facts and evidence.”

Privately, Republicans on Capitol Hill have said they are trying to give Trump the time and space he needs to come to grips with the election results.

“Well, I think he’s got a right, a constitutional right, if there are legal challenges they want to make,” said Sen. John Thune, the No. 2 Republican. “Let those play out.”

Republican lawmakers are hesitant to push Trump to concede to Biden, knowing it would anger their base of Trump’s most devoted supporters. But the Republican lawmakers are not overtly encouraging the president’s claims of fraud, even as they allow questions to linger.

Only a handful of Republicans, including Sens. Susan Collins, Mitt Romney and Lisa Murkowski, have congratulated Biden on the election.

“Stay out of the fray,” as one Republican aide put it. The aide and other Republicans were granted anonymity to frankly discuss the situation.

Whatever the position, “you’re going to anger half the country,” said another Republican on Capitol Hill.

At the same time, Republicans are feeling increasingly unmoored from the White House. Trump himself has not been returning some senators’ phone calls, one of the aides said.

Scalise said he spoke to Trump a few days ago and said the president "left it all on the field” in the campaign.