Election 2020 Trump

President Donald Trump speaks at the White House, Thursday, Nov. 5, 2020, in Washington. (AP Photo/Evan Vucci)

President Donald Trump staged a corrosive and potentially dangerous attempt at undermining the US election on Thursday, baselessly claiming the presidency was being stolen from underneath him as vote counts showed his path to victory disappearing.

Standing at the White House podium, the President repeated false claims that a count of legally cast ballots would show him winning against former Vice President Joe Biden. He complained that in certain states where he had been leading on election night, tallies have been "whittled down" or have shown his rival leading.

Using the briefing room to espouse baseless claims he is being deprived a second term by fraud, Trump thrust into question the democratic notion of a peaceful transition of power should Biden win. Instead he suggested he would fight in the courts until the election is decided in his favor.

"This is a case where they're trying to steal an election, they're trying to rig an election, and we can't let that happen," Trump said in a dour monotone, providing no evidence and departing the room without answering for his false claims.

The spectacle, though foreshadowed by the President for months, was nevertheless a sign of Trump's unwillingness to cede the White House without a prolonged battle. Even as he complained that his own race had been rigged, Trump used the occasion to trumpet down-ballot wins by Republicans without explaining why those races wouldn't be similarly afflicted by his claims of fraud.

His message came as new tallies show his lead dwindling in Georgia and Pennsylvania, where mail-in ballots are still being counted.

Trump spent the past six months decrying the use of mail-in ballots, a strategy even some Republicans feared would suppress his own totals. While Trump retains a pathway to 270 electoral votes, it has grown smaller by the hour.

The President had not been seen in public since his middle-of-the-night speech on Wednesday, when he falsely declared victory. Aides said Biden's public appearances on Wednesday and Thursday -- during which he called for patience and calm as the votes are counted -- prompted Trump to push harder to do the same, though some had hoped to avoid the type of speech the President ultimately delivered.

Despite campaign assurances that the numbers will eventually break their way -- and despite the President's apparent desire for a battle -- reality was setting in for several of Trump's aides in the White House and campaign.

Senior advisers privately acknowledged the math simply wasn't on their side and were preparing for a loss. Others privately acknowledged the chances of Trump winning are now slim and were contemplating their next career steps.

But that reality hasn't appeared to have set in for the candidate himself. Before his briefing room appearance, Trump continued to make a series of phone calls overnight, stung that his lead in some states had vanished and convinced Biden is stealing the presidency.

Entrenched at the White House with no public events on his schedule, Trump has personally dispatched advisers to battlegrounds across the country hoping to wage legal fights in places where the margins remain tight.

That has included his two adult sons, who voiced frustration on Thursday that more Republicans weren't publicly backing the President in his battle to halt vote counting.

"Where is the GOP?! Our voters will never forget..." wrote Eric Trump. His older brother, Donald Trump Jr., accused "2024 GOP hopefuls" of remaining silent in the effort.