The House on Wednesday began a historic debate on articles of impeachment that charge President Trump with abusing his power in dealings with Ukraine and obstruction of Congress — which, if approved, would make Trump the third president in US history to be impeached.

The vote, which is expected to be highly partisan, caps months of investigation by House Democrats into whether Trump leveraged nearly $400 million in military aid and a White House visit to coerce Ukraine to launch an investigation into Joe Biden, a 2020 political rival.

House Speaker Nancy Pelosi announced the start of the impeachment inquiry on Sept. 24 after reports on a whistleblower’s complaint revealed Trump’s July 25 phone call with Ukrainian President Volodymyr Zelensky seeking the investigation into Biden and his son Hunter.

The following day, the White House released a rough transcript of the call in which, during a discussion about Ukraine buying more military hardware, Trump tells Zelensky: “I would like you to do us a favor though.”

Trump has characterized his 30-minute conversation with Zelensky as “perfect,” but Democrats said it is evidence that Trump was seeking something of value to him politically — an investigation into Biden.

After weeks of testimony from current and former diplomats and administration officials in the House Intelligence Committee, the House Judiciary Committee last Friday approved the two articles of impeachment, setting the stage for Wednesday’s debate in the full House.

Trump, who fired off a six-page letter to Pelosi on Tuesday, took to Twitter on Wednesday to directly address the threat of impeachment.

“Can you believe that I will be impeached today by the Radical Left, Do Nothing Democrats, AND I DID NOTHING WRONG! A terrible Thing. Read the Transcripts. This should never happen to another President again. Say a PRAYER!,” he posted on his Twitter.

In the letter to Pelosi, Trump blasted Democrats for attempting a “coup.”

“By proceeding with your invalid impeachment, you are violating your oaths of office, you are breaking your allegiance to the Constitution, and you are declaring open war on American Democracy,” he said.

Pelosi sent a letter to Democrats on Tuesday evening urging them to join her on the House floor for the beginning of the debate.

“Our constituents look to us to be respectful of the Constitution and Defenders of our Democracy, and to proceed in a manner worthy of our oath of office to support and defend the Constitution of the United States,” the California Democrat wrote.

According to the parameters set by the House Rules Committee, which met for more than 10 hours on Tuesday, there will be six hours of debate — evenly split between Democrats and Republicans — over the articles of impeachment.

No Republicans are expected to vote for impeachment.

According to reports, Pelosi has enough Democratic votes to surpass a simple majority.

Once the articles are passed by the House, the GOP-controlled Senate is expected to take them up and hold a trial to determine whether Trump should be removed from office.

A two-thirds majority vote is needed to oust the president.