John Fund asks at National Review Online whether U.S. Rep. Justin Amash’s defection from the Republican Party could cost President Trump his re-election.

Now that Representative Justin Amash has left the Republican party, he’ll be getting some calls asking whether he plans to run for president in 2020. Never Trumpers and consultants and left-wing billionaires will be jostling with Libertarian-party leaders for meetings with him — all convinced that his candidacy could drain enough votes to sink Trump’s reelection.

The five-term Michigan congressman left the Republican party last week to become an independent. He claims he plans to run for reelection to his Grand Rapids seat under that banner. But he told CNN on Sunday that he hasn’t closed the door on a White House bid.

“I still wouldn’t rule anything like that out,” he said. “I have to use my skills, my public influence, where it serves the country best.”

If he ran, Amash could run as an independent, but that would involve a grueling ballot-access campaign. If he ran as a Libertarian, he would probably be able to immediately secure a place on the ballot of some 40 states where Libertarians are already a qualified party.

While he didn’t mention President Trump in his GOP-departure announcement, it’s clear that the 39-year-old Amash doesn’t see himself as a good fit in a Trump-led party. In May, he announced he had seen enough evidence in the Mueller report to support impeaching Trump for obstruction of justice.

Naturally, President Trump dismissed Amash’s move by calling him “a total loser” in a tweet. But Trump aides say that an Amash 2020 candidacy could pose real challenges to both Trump and any Democratic nominee.