Appearing on Fox News on Wednesday morning, Karl Rove, the veteran Republican strategist, seemed a bit bemused. "We have two Presidencies under way," he said. In one of them, Donald Trump was "looking strong and fulfilling his campaign promises," Rove explained. He was referring to a series of executive orders that Trump had issued in policy areas ranging from health care to trade to the environment. While these edicts outraged many liberals and moderates, they were broadly in line with what the new President had pledged to do.

But there is a second President Trump, Rove added, one who "gets involved in food fights over how many people showed up at his Inauguration, and whether three to five million people voted illegally in the election . . . The latter President is not helpful for the ultimate success of Donald Trump." His voice rising, Rove went on, "There is no evidence whatsoever that three million to five million illegals voted in this election."

Rove's exasperation was probably shared by some of Trump's staff. On Tuesday, Trump had seemed ready to move on from his assertion that only massive voter fraud had prevented him from winning the popular vote, in November—a false claim that has inspired widespread criticism and ridicule. "Big day planned on NATIONAL SECURITY tomorrow," Trump tweeted, on Tuesday night. "Among many other things, we will build the wall!"

On Wednesday, Trump was scheduled to speak at the Department of Homeland Security. His staff had let it be known that he would be signing some fresh executive orders concerning the construction of a border wall and new restrictions on immigration. Because these issues had been central to Trump's campaign platform, it made sense, from the White House's perspective, to clear the entire day for them.

But, instead of going along with that plan, Trump returned to the subject of voter fraud. In a pair of tweets posted early on Wednesday morning, he promised to launch a "major investigation" into the issue. The probe would include "those registered to vote in two states, those who are illegal and . . . even, those registered to vote who are dead (and many for a long time)," Trump wrote. He added, "Depending on results, we will strengthen up voting procedures."

Afterward, Rove wasn't the only conservative analyst who sensed danger in Trump's hypersensitivity and his unwillingness to go along with the usual conventions of Presidential marketing. This normally includes a rough adherence to some proximity of the truth and a rigid adherence to the agreed-upon message of the day. "Trump’s appointments and initial executive orders are winning praise from former conservative critics, while flummoxing the Left," Victor Davis Hanson, a military historian and fellow at the Hoover Institution, wrote Wednesday, for the National Review. But Hanson criticized Trump for getting diverted into periphery issues, saying, "Trump's fate is in the hands of Trump alone . . . the only obstacle on the horizon is playing into the hands of those who wish to destroy him."

As it happens, we can be pretty sure that Trump's won't change his ways. His narcissism knows no bounds, and he lives by the principle that he should never back down, even when it is proven that he has spouted outrageous falsehoods. The issue is how much these traits will harm Trump. For "those who wish to destroy him”—including Democrats and a diminishing band of Never Trump Republicans, plus anybody who cherishes the values of honesty, inclusiveness, internationalism, and freedom of expression and religion—the problem with Hanson's analysis is that they don't actually have the power to bring about such an outcome.

Right now, the only people with the capacity to stop Trump are Mitch McConnell, Paul Ryan, and their Republican colleagues in Congress. At the minimum, they could refuse to go along with some of his more illiberal proposals; at the maximum, they could theoretically invoke the Twenty-fifth Amendment and deem him unfit for office. The overwhelming likelihood is that they will do neither of these things.

On Tuesday, Ryan did say that he had "seen no evidence" of widespread voter fraud, but he refused to be drawn out any further. McConnell bowed and scraped to Trump, saying that voter fraud "does happen." Other Republicans made similar weaselly statements. And, of course, some of the shock jocks and right-wing outriders who cheered Trump to victory supported his incendiary assertions.

Because G.O.P. legislators in many parts of the country have used similarly dubious allegations to justify voter-suppression efforts, this response shouldn't have been surprising. As Trump has done many times before, he took a bogus issue that Republicans have pursued for years and exploited it for his own purposes. Some Party elders and commentators might have concerns, but that's not because he’s undermining a basic institution of democracy—it’s largely because they fear that he will alienate moderate voters. And if Trump's proposed investigation does serve as a pretext for legislation designed to make it harder for minorities, immigrants, and poor people to vote, that will be just fine by the G.O.P.

As long as Trump pursues a policy agenda that Republicans support, and which they played a large role in crafting, they will continue to shrug off his nuttier and more despotic tendencies. That is a lesson the past few days should have taught us.