President Trump fired off a scathing letter to House Speaker Nancy Pelosi Tuesday, decrying the impeachment vote likely to come this week — and charging that Democrats were “declaring open war on American Democracy.”

The House impeachment proceedings, he railed, were “an unprecedented and unconstitutional abuse of power by Democratic lawmakers unequaled” in the country’s history.

“The Articles of Impeachment . . . include no crimes, no misdemeanors and no offenses whatsoever,” Trump wrote in the six-page missive, adding, “By proceeding with your invalid impeachment . . . you are declaring open war on American Democracy.”

Trump also took a dig at Pelosi for what he called her insulting comment — that she prays for him.

“You are offending Americans of faith by continually saying, ‘I pray for the President,’ when you know this statement is not true, unless it is meant in a negative sense,” Trump wrote.

“It is a terrible thing you are doing, but you will have to live with it, not I!”

Pelosi had “cheapened the importance of the very ugly word, impeachment!” he added, charging that Democrats only wanted to overturn the 2016 election.

“Everyone, you included, knows what is really happening,” Trump said. “Your chosen candidate lost the election in 2016, in an Electoral College landslide (306-227), and you and your party have never recovered from this defeat. So you have spent three straight years attempting to overturn the will of the American people and nullify their votes. You view democracy as your enemy!”he wrote.

“You are the ones interfering in America’s elections. You are the ones subverting America’s Democracy. You are the ones Obstructing Justice. You are the ones bringing pain and suffering to our Republic for your own selfish personal, political, and partisan gain.”

The House Rules Committee was meeting to set rules for the impeachment debate, which could begin as early as Wednesday.

In the letter to Pelosi, Trump brought up then-Vice President Joe Biden’s threat to withhold International Monetary Fund aid to Ukraine, and alleged that he did so to protect his son Hunter, who had scored a lucrative position on a Ukraine energy giant’s board of directors.

There is no known evidence that either Biden did anything wrong.

Trump also said he was being treated worse than accused witches who were executed in Colonial America.

“More due process was afforded to those accused in the Salem Witch trials,” Trump wrote, noting that even Ukraine President Volodymyr Zelensky had repeatedly said that he felt no undue pressure from the White House.

House Democrats contend Trump abused his power by asking Zelensky to launch probes of the Bidens while withholding military aid from Ukraine.

The president also warned that Pelosi and Democrats would pay a political price for the impeachment proceedings.

“I have no doubt the American people will hold you and the Democrats accountable in the upcoming 2020 election. They will not soon forgive your perversion of justice and abuse of power,” he wrote, adding that he wanted the letter to leave a record for history.

“It is time for you and the highly partisan Democrats in Congress to immediately cease this impeachment fantasy and get back to work for the American people,” Trump wrote.

“While I have no expectation that you will do this, I write this letter to you for the purpose of history and to put my thoughts on a permanent and indelible record.”

Finally, Trump slammed Pelosi for invoking “the Founding Fathers in pursuit of this election-nullification scheme” and said he would be vindicated by history.

“One hundred years from now, when people look back at this affair, I want them to understand it, and learn from it, so that it can never happen to another president again,” he concluded.

The Democratic-controlled House is expected to vote mainly along party lines to impeach the commander in chief.

Pelosi’s office did not immediately respond to a request for comment.