President Donald Trump has a new nickname for Sen. Jeff Flake, the retiring Arizona Republican and vocal Trump critic. “Sen. Jeff Flake(y) who is unelectable in the Great State of Arizona (quit race, anemic polls) was caught (purposely) on ‘mike’ saying bad things about your favorite President,” the president tweeted Sunday evening.

Flake was caught on a hot mic this weekend saying the GOP is “toast” if it continues in the vein of Trump and far-right Alabama Senate candidate Roy Moore — a comment that clearly irked the president.

But while Flake, who announced his retirement with a scathing Senate floor speech about the fading morality of the Republican Party, has been a vocal critic of Trumpism, he hasn’t had as many contrarian positions on the GOP’s agenda.

Notably, Flake has voted with the president 90 percent of the time, supported the Republicans’ doomed health care effort, and hasn’t voiced his opinion either way on the tax bill. In other words, he’s not too “flaky” of a vote.

It’s what makes the rest of Trump’s tweet even riskier — the president is assuming Flake is going to vote “no” on the tax bill.

Sen. Jeff Flake(y), who is unelectable in the Great State of Arizona (quit race, anemic polls) was caught (purposely) on “mike” saying bad things about your favorite President. He’ll be a NO on tax cuts because his political career anyway is “toast.” — Donald J. Trump (@realDonaldTrump) November 19, 2017

Either Trump knows something about Flake’s position on tax reform that the rest of Washington isn’t too sure of or he’s antagonizing someone who could be a crucial vote on the tax bill.

Senate Republicans, who are hoping to rush through a massive tax reform package the week after Thanksgiving, can only lose two votes and still pass the bill. Already there have been some skeptical voices from lawmakers like Sens. Susan Collins (R-ME) and Bob Corker (R-TN), and one stated “no” vote from Sen. Ron Johnson (R-WI).

There are reasons Flake, a known conservative and strong deficit hawk, could conceivably vote against this tax bill, which will increase the national debt by $1.5 trillion in the first 10 years and then sunset almost all the individual tax cuts to prevent the deficit from increasing past the 10-year window.

One insult from the president is unlikely to turn Flake against the effort, but it certainly isn’t an effective lobbying effort to get Republican unity on the bill.