President Donald Trump said Friday that Democrats were purposely helping former Vice President Joe Biden in the presidential primary by delaying the Senate impeachment trial.

“They are rigging the election again against Bernie Sanders, just like last time, only even more obviously,” Trump wrote on Twitter.

Current Democrat Senators Bernie Sanders, Elizabeth Warren, and Amy Klobuchar will be called back to Washington, DC, for the impeachment trial that is expected to begin next week. That means Democrats will be occupied in Washington for at least two weeks rather than campaigning in Iowa.

But Trump focused on Sanders as the biggest political victim of the impeachment calendar.

“They are bringing him out of so important Iowa in order that, as a Senator, he sit through the Impeachment Hoax Trial,” Trump wrote.

The Iowa caucuses will be held in just 17 days.

Sanders said he would have preferred to stay in Iowa.

“Between you and me I’d rather be here in Iowa, but I have a constitutional responsibility, which I accept as a United States senator, to be a juror in Trump’s impeachment trial,” he said.

Trump argued House Speaker Nancy Pelosi purposefully delayed the trial.

“Crazy Nancy thereby gives the strong edge to Sleepy Joe Biden, and Bernie is shut out again,” Trump wrote. “Very unfair, but that’s the way the Democrats play the game.”