WASHINGTON — Some Republican senators have publicly acknowledged Democrat Joe Biden is the president-elect. Others have moved straight to criticizing his early Cabinet picks, even as President Donald Trump continues to dispute the outcome of the Nov. 3 election.

But Senate Majority Leader Mitch McConnell, R-Ky., three weeks after Election Day, has still not said much of anything at all.

McConnell’s ongoing silence, even as the Trump administration moves to allow Biden to start his transition, leaves a question mark over what could be the most important Washington relationship of the next two years – between an incoming president who promised to tackle the nation’s most pressing concerns and the win-at-all-costs Capitol Hill operator who may well serve as his legislative gatekeeper.

The two men – Senate colleagues for 24 years and sparring partners in several high-stakes negotiations during Biden’s time as vice president – still have not spoken since the election, according to a GOP aide who spoke on the condition of anonymity to talk frankly.

McConnell has not publicly commented since Nov. 17, when he offered circumspect remarks on the election and Trump’s legal challenges based on unfounded claims. “What we all say about it is frankly irrelevant,” he said. “All of it will happen right on time, and we’ll swear in the next administration on Jan. 20.”

Since then, Biden has made his initial round of Cabinet nominations, eschewing some potentially controversial picks in favor of pillars of the Democratic policy establishment, while some prominent Senate Republicans with their own presidential ambitions are already signaling their intention to stand against confirmation.

Biden’s choices – which include Antony Blinken for secretary of state, Alejandro Mayorkas for secretary of homeland security and Avril Haines for director of national intelligence – all held high-ranking positions in the Obama administration.

In tweets this week, Sen. Marco Rubio, R-Fla., called Biden’s early nominees “polite & orderly caretakers of America’s decline,” while Sen. Josh Hawley, R-Mo., referred to them as “a group of corporatists and war enthusiasts – and #BigTech sellouts” and Sen. Tom Cotton, R-Ark., dismissed them as “panda huggers who will only reinforce his instincts to go soft on China.”

All three men, potential 2024 presidential nominees, rarely, if ever, criticized the norm-shattering Trump and his revolving door of administration officials.

But other Republican senators – such as Susan Collins of Maine, Lisa Murkowski of Alaska and Mitt Romney of Utah – have congratulated Biden and indicated that they are inclined to confirm his nominees who swim in the ideological mainstream.

Should Republicans retain control of the Senate after a pair of Jan. 5 runoff elections in Georgia, it will be in McConnell’s hands whether and when to bring those nominees to the Senate floor for a vote – a decision that will require balancing the wishes of the GOP ranks with Biden’s right to assemble a team of his choosing.

“To the United States Senate, I hope these outstanding nominees receive a prompt hearing and that we can work across the aisle in good faith to move forward for the country,” Biden said Tuesday as he introduced the nominees.

McConnell has yet to acknowledge Biden is the president-elect, let alone lay out his thinking on the confirmation of a Democratic president’s nominees. But GOP aides say he is unlikely to orchestrate a complete blockade.

When Republicans controlled the Senate during the final two years of Barack Obama’s presidency, McConnell advanced several Cabinet-level nominees such as Defense Secretary Ashton Carter and Attorney General Loretta Lynch, while leaving dozens of judicial vacancies unfilled – paving the way for Trump’s remaking of the federal courts.

Still, there are warning signs for Biden’s picks: Mayorkas did not win a single Republican vote when he was confirmed as deputy homeland security secretary in 2013; Blinken won only two GOP votes – from a pair of now-retired senators – when he was confirmed as deputy secretary of state in late 2014, two weeks before McConnell became majority leader.

Another factor in McConnell’s silence is his long-standing policy to not say anything more than strictly necessary – especially when it comes to Trump, lest he inflame the president in counterproductive ways.

Multiple Republicans who spoke on the condition of anonymity this week say McConnell probably has an eye toward the unfinished business of the 116th Congress – including the need to secure a government funding accord ahead of a Dec. 11 shutdown deadline – as well as his desire to avoid national security related shake-ups that he and most Republicans oppose.

Among them are a threatened complete pullout of U.S. troops from Afghanistan – which McConnell publicly opposed in a Senate floor speech last week – and the potential firings of FBI Director Christopher Wray and CIA Director Gina Haspel. McConnell hosted Haspel for a meeting in his office earlier this month in what many observers saw as a gesture of support as Trump cleared out the top Pentagon ranks and threatened to expand the post-election purge.

Publicly, Trump has shown little engagement with matters of government as he continues to stoke baseless claims of rampant voter fraud in an attempt to have the courts and potentially state legislators overturn Biden’s victory. He appeared in the White House briefing room Tuesday for barely one minute to commemorate a record high for the Dow Jones industrial average and later presided over the annual ceremonial turkey pardoning without addressing the election or taking questions from reporters.

McConnell has frequently sidestepped comment on Trump’s public controversies and rhetorical excesses, keeping his own counsel private – even as fellow Republicans, many of them steeped in conservative ideology, were publicly rankled. During Trump’s presidential candidacy and the first two years of his term, McConnell found ways to carefully modulate his words while then-House Speaker Paul Ryan, R-Wis., would more forthrightly criticize Trump.

Almost two years after Ryan left the House, that pattern continues to hold. While McConnell stays mum, Ryan told a business conference Tuesday that Trump ought to concede and “embrace the transfer of power,” while offering tough criticism of his efforts to cast doubt on the election results.

“I know firsthand what it’s like to lose a national election, and it is a terrible feeling,” Ryan said, appearing at Bank of America’s virtual European Credit Conference on Tuesday. “But I think it’s really important that we’re clear about this. . . . The election is over. The outcome is certain, and I really think the orderly transfer of power is one of the most uniquely fundamental American components of our political system. And I think it’s really important that we respect the will of the people, and if we don’t, we will end up doing damage to our country, to our democratic institutions, to norms and to the cause of freedom.”

But, Ryan added, he believed it would be “in Joe Biden’s best interest” for Republicans to win the Georgia elections and keep McConnell in control of the Senate: “He does know how to work in divided government. He does put deals together, and that will be made much, much easier for him to operate like that and bring sides together if we truly have divided government.”