President Trump is blasting the Democrats — for not supporting Bernie Sanders.

“They are rigging the election again against Bernie Sanders, just like last time, only even more obviously. They are bringing him out of so important Iowa in order that, as a Senator, he sit (sic) through the Impeachment Hoax Trial. Crazy Nancy (Pelosi) thereby gives the strong edge to Sleepy Joe Biden and Bernie is shut out again,” Trump said Friday in a series of tweets. “Very unfair, but that’s the way the Democrats play the game.”

Sanders, predictably, was having none of it.

“Let’s be clear about who is rigging what: it is Donald Trump’s action to use the power of the federal government for his own political benefit that is the cause of the impeachment trial,” Sanders tweeted in response. “Democrats are going to unite to sweep him out of the White House in November.”

Trump is rehashing his old knock on the Democratic establishment ahead of his impeachment trial, which will take Sanders and fellow U.S. Senators Elizabeth Warren, Amy Klobuchar and Michael Bennet off the campaign trail before the Iowa caucuses to serve as jurors.

Yet, Trump and Sanders are more alike than they seem — a pair of unapologetic populists with deeply entrenched bases who inhabit opposite ends of the political spectrum.

Less than three weeks before voting begins, Sanders is polling first in New Hampshire, second in Iowa and second nationally, according to Real Clear Politics averages. He came in second in this past week’s Franklin Pierce University-Boston Herald-NBC10 poll just behind former Vice President Joe Biden and in front of Warren.

“Bernie Sanders will never be part of the Democratic establishment, so they don’t want him to win,” said Republican strategist Mike Dennehy. “I think Donald Trump can sympathize with Bernie Sanders’ position.”

But Trump could be pumping up Sanders to further divide Democratic voters and give himself an easier path back to the White House.

“The party won’t coalesce around Bernie,” Dennehy added. “It’s no secret that Donald Trump is just trying to fire up the Democrats — really the establishment and the progressives — and trying to instigate a fight because he knows he’s got a better chance against Bernie Sanders than he does against Joe Biden.”