Sen. Bernie Sanders is warning that President Trump is going “down the path of authoritarianism” by refusing “to commit to a peaceful transition of power if he loses the election.”

The progressive senator from Vermont and runner up in the 2020 Democratic presidential primaries – in a speech Thursday in the nation’s capital – stressed that this year’s presidential election “is not just an election between Donald Trump and Joe Biden. This is an election between Donald Trump and democracy – and democracy must win.”

TOP REPUBLICANS MCCONNELL, ROMNEY, PUSH BACK AT TRUMP'S CONTROVERSIAL PEACEFUL TRANSFER OF POWER COMMENTS

The two-time Democratic presidential candidate and populist champion spoke the day after Trump – when asked at a White House briefing if he’d commit to a peaceful transfer of power if he loses the presidential election – said “we’re going to have to see what happens.”

The president – who for months has made unsubstantiated claims that a surge in voting by mail due to serious health concerns over in-person voting at polling stations amid the coronavirus pandemic would lead to a “rigged election” – stressed that “I’ve been complaining very strongly about the ballots, and the ballots are a disaster. We want to get rid of the ballots and you’ll have a very peaceful – there won’t be a transfer, frankly. There will be a continuation.”

Sanders, pushing back against the president’s comments, emphasized “that’s not his choice. That’s for the American people to determine. Let us be very clear. There is nothing in our Constitution or in our laws that give Donald Trump the privilege of deciding whether or not he will step aside if he loses.”

The president’s controversial comments sparked immediate pushback not just from Democrats but also top Republicans in Congress.

Senate Majority Leader Mitch McConnell – the most powerful Republican in Washington following the president – tweeted Thursday morning that “The winner of the November 3rd election will be inaugurated on January 20th. There will be an orderly transition just as there has been every four years since 1792.”

Sanders – in his first in-person speech since ending his presidential campaign in April – warned that the country faces a danger “from a president who is a pathological liar, who has strong authoritarian tendencies, who neither understands nor respects our Constitution and who is prepared to undermine American democracy in order to stay in power.”

PELOSI SAYS TRUMP'S TRYING TO HAVE CONSTITUTION 'SWALLOW CLOROX'

And he charged that the peaceful transition of power, which he called “the bedrock of American democracy, is being threatened like never before.”

Sanders urged that with less than six weeks to go until Election Day, “that all Americans – Democrats, Republicans, independents, progressives, moderates, conservatives – come together to defend American democracy, our Constitution and the rule of law” and ensure that the nation has “an election in which all votes are counted and an election in which the loser accepts the results.”

The senator pointed to controversial comments the president made last month at the Republican National Convention, when Trump charged that “the only way they can take this election away from us is if this is a rigged election.”

Sanders argued that what the president is saying “is that if he wins the election, that's great. But if he loses, it’s rigged, because the only way, the only way, he can lose is if it's rigged. And if it’s rigged, then he is not leaving office. Heads I win. Tails you lose. In other words, in Trump's mind, there is no conceivable way that he should leave office.”

Speaking directly to the president, Sanders said “let me make this clear to Donald Trump: Too many people have fought and died to defend American democracy. You are not going to destroy it. The American people will not allow that to happen.”

Sanders claimed that the president – who narrowly trails Biden in the latest public opinion polls in many of the key battleground states where the presidential election will be won – “is attempting massive voter suppression. He and his Republican colleagues are doing everything they can to make it harder and harder for people to vote. In addition, he is sowing the seeds of chaos, confusion and conspiracy theories by casting doubt on the integrity of this election and, if he loses, justifying why he should remain in office.”

"Trump's strategy to delegitimize this election and to stay in office if he loses is not complicated," Sanders said. "Finding himself behind in many polls, he is attempting massive voter suppression."

The senator called “on every elected official in America whether they be Republican, Democrat or Independent to vigorously oppose voter suppression and voter intimidation, to make sure that every vote is counted, and that no one is declared the winner until those votes are counted.”

And as a leading supporter of the former vice president, Sanders stressed that “a landslide victory for Biden will make it virtually impossible for Trump to deny the results and is our best means for defending democracy.”