Ever since Donald Trump became a politician, he has upended electoral norms and disregarded presidential traditions. Yet as he took the stage to declare victory on election night, Trump did something utterly conventional: He claimed to have a mandate.

“America has given us an unprecedented and powerful mandate,” the president-elect exulted, describing his win as a victory for “the greatest political movement of all time.”

His words were characteristically grandiose. But in announcing that the voters had rewarded him with a go-ahead to carry out his platform, Trump was making a claim that newly elected presidents and their allies always make.

Four years earlier, almost to the day, the newly elected Joe Biden proclaimed that voters had just presented him with “a mandate for action on COVID, the economy, climate change, systemic racism.” Four years before that, after Trump’s first election in 2016, then-House Speaker Paul Ryan marveled at his “incredible political feat” and declared: “He just earned a mandate.”

For nearly two centuries, presidents have been claiming that their election confers on them the political right and moral authority to do what they campaigned on. The claim dates back to Andrew Jackson, who insisted that as the only official elected to represent the whole nation, a president is entitled to carry out his platform with “as few impediments as possible.” That isn’t what the Constitution says and it isn’t how our system works, but that never stops presidents and presidential loyalists from invoking the M-word.

“The myth of the mandate is now a standard weapon in the arsenal of persuasive symbols all presidents exploit,” Robert Dahl, a professor of political science at Yale, wrote in 1990. At times presidents have deployed that weapon with almost comical audacity. In 1973, as the Watergate storm clouds were gathering, Richard Nixon went on television to insist that the scandal must not be allowed to interfere with the “mandate” bestowed by his reelection the previous November. “If you want the mandate you gave this administration to be carried out,” Nixon told the nation, then “those who would exploit Watergate” must not be allowed to succeed.

It was a wholly self-serving claim, of course. But Nixon’s “mandate” claim had at least one thing in its favor: He had won the 1972 election by one of the greatest landslides in presidential history, carrying 49 states and pulling nearly 61 percent of the popular vote. As an objective legal matter, a president’s margin of victory is irrelevant to his constitutional authority. In terms of practical politics, however, a candidate who surges into office with support from a sweeping majority of the electorate is likely to be seen as having earned more leeway to pursue his priorities than a candidate who barely edged out his opponent.

Trump is in the “barely edged” category. He won the election with 49.9 percent of the popular vote to Kamala Harris’s 48.3 percent — a margin of just 1.6 percentage points, one of the tiniest in history. In the Electoral College, Trump will get 312 votes, or 58 percent of the total. As political analyst Chris Stirewalt points out, that will leave him “tied with James Garfield in the election of 1880 at 44th biggest victory out of 60 presidential elections.”

Trump won the election fair and square. But it is absurd to imagine that he now possesses “an unprecedented and powerful mandate” or that he is leading “the greatest political movement of all time.” Americans were pretty evenly divided heading into the election and they remain pretty evenly divided coming out of it. Trump’s haul of 76 million popular votes is certainly impressive; Harris’s total of 74 million votes is scarcely less so. Republicans gained the White House and a slim Senate majority not because a massive tsunami broke in their favor but because of a slight red shift, wide but very shallow. Considering how evenly split the parties are, and how frequently control of the White House and the congressional chambers has flipped in recent years, it is entirely reasonable to expect a similar shift in the other direction the next time voters go to the polls.

None of which means that Trump shouldn’t try to implement his policy priorities or that Republicans in Congress shouldn’t try, within reason, to help him. It does mean that when Trump returns to the White House in January, it will be as the president of a still deeply polarized nation in which consensus on almost anything is nonexistent. Democrats lost the election because they overreached and made themselves somewhat more unpopular than the other party. Unless Trump and the GOP want to make the same mistake, they ought to cool the “mandate” talk, rein in their crazies, and prove that they can govern like adults.