The Trump administration’s war on truth continues with that old voter-fraud lie.

White House Press Secretary Sean Spicer on Tuesday reiterated President Donald Trump’s baseless belief that millions of people voted illegally in last November’s presidential election—a stunning and deeply dangerous claim that threatens to undermine the legitimacy of American democracy itself:

“I think he stated his concerns—voter fraud and people voting illegally—during the campaign, and he continues to maintain that belief based on studies and evidence that people have presented to him,” Spicer said. He provided no specific evidence to support the assertion. When asked whether the government would investigate such a dramatic claim, he replied, “Maybe we will.”

Leading Republicans rebuked Trump over this madness on Tuesday, with House Speaker Paul Ryan reiterating that he’s seen “no evidence” for millions of fraudulent votes. “I am begging the president,” South Carolina Senator Lindsey Graham said. “Share with us the information you have about this or please stop saying it.”

The petty intent of Trump’s claim is to undermine Hillary Clinton’s national popular vote victory of more than two million votes, but the consequences could be severe: Many Americans might refuse to accept the outcome of U.S. elections and begin to question the legitimacy of all elected officials. Or maybe it will backfire, and Americans will question the legitimacy of just one elected official in particular.