WASHINGTON (AP) — Democrat Joe Biden was on the cusp of winning the presidency Friday night after he opened up narrow leads over President Donald Trump in critical battleground states.

Biden had leads in Pennsylvania, Nevada and Georgia, putting him in a stronger position to capture the 270 Electoral College votes needed to take the White House. The winner will lead a country facing a historic set of challenges, including the surging pandemic and deep political polarization.

The focus was on Pennsylvania, where Biden led Trump by more than 16,000 votes, and Nevada, where the Democrat led by about 22,000, as Americans spent a third full day after the election without knowing who will lead them for the next four years. The prolonged process added to the anxiety of a nation whose racial and cultural divides were inflamed during the heated campaign.

Biden was at his home in Wilmington, Delaware, as the vote count continued, and aides said he might address the nation in primetime. Trump stayed in the White House and out of sight, as more results trickled in, expanding Biden’s lead in must-win Pennsylvania. In the West Wing, televisions remained tuned to the news amid trappings of normalcy, as reporters lined up for coronavirus tests and outdoor crews worked on the North Lawn on a mild, muggy fall day.

Trump’s campaign, meanwhile, was quiet — a dramatic difference from the day before, when it held a morning conference call projecting confidence and held a flurry of hastily arranged press conferences announcing litigation in key states.

A handful of states remained in play Friday evening, with Georgia, North Carolina, Pennsylvania and Nevada all too early to call. In all four states the margins between Trump and Biden were too narrow and the number of ballots left to be counted too great for the AP to declare a victor.

In Pennsylvania, officials were not allowed to begin processing mail-in ballots until Election Day under state law. In Nevada, there were a number of provisional ballots cast by voters who registered on Election Day, and officials had to verify their eligibility. And recounts could be triggered in both Pennsylvania and Georgia.

With his pathway to reelection appearing to greatly narrow, Trump was testing how far he could go in using the trappings of presidential power to undermine confidence in the vote.

On Thursday, he advanced unsupported accusations of voter fraud to falsely argue that his rival was trying to seize power in an extraordinary effort by a sitting American president to sow doubt about the democratic process.

“This is a case when they are trying to steal an election, they are trying to rig an election,” Trump said from the podium of the White House briefing room.

He took to Twitter late Friday to pledge further legal action, tweeting “Joe Biden should not wrongfully claim the office of the President. I could make that claim also. Legal proceedings are just now beginning!”

Trump did claim that he won late on Election Night. He also tweeted that he had “such a big lead in all of these states late into election night, only to see the leads miraculously disappear as the days went by,” although it was well known that votes cast before Tuesday were still being legally counted.

Biden spent Thursday trying to ease tensions and project a more traditional image of presidential leadership. After participating in a coronavirus briefing, he declared that “each ballot must be counted.”

“I ask everyone to stay calm. The process is working,” Biden said. “It is the will of the voters. No one, not anyone else who chooses the president of the United States of America.”

Trump’s erroneous claims about the integrity of the election challenged Republicans now faced with the choice of whether to break with a president who, though his grip on his office grew tenuous, commanded sky-high approval ratings from rank-and-file members of the GOP.

That was especially true for those who are eyeing presidential runs of their own in 2024.