Top House Democrats unveiled two articles of impeachment against Donald Trump on Tuesday, laying the foundation for a vote that could see the president become just the third American leader in history to be impeached.

The articles of impeachment relate to two actions by Trump: One is abuse of power linked to his demand that the Ukrainian president investigate a political rival, and the second is obstructing Congress in its effort to investigate the behavior.

Democrats signaled on Monday that the chamber’s investigations were coming to a close after current and former administration officials testified about Trump’s behavior during a whirlwind month of House impeachment hearings.

In a series of bombshell revelations, the aides detailed an effort by Trump and his aides to pressure Ukrainian President Volodymyr Zelensky to open an investigation into a prime Democratic rival, former Vice President Joe Biden, and Biden’s son, Hunter. Democrats cast the demand as a clear quid pro quo in which Trump would release nearly $400 million in security aid and arrange a coveted visit to the White House for the newly elected Ukrainian leader.

Republicans, however, have largely remained steadfast behind the president, accusing House Speaker Nancy Pelosi (D-Calif.) and her leadership team of attempting to overturn the 2016 election and unfairly attacking the president. The GOP has admitted that Trump made the demand of Ukraine, but said there is no evidence that it amounted to a quid pro quo.

The House Judiciary Committee, tasked with drafting the articles against Trump, laid out its case against the president during a marathon day of hearings on Monday that saw several dramatic clashes with Republican lawmakers.

Trump’s “pattern of misconduct undermines our national security and our free and fair elections,” Judiciary Committee Chairman Jerry Nadler (D-N.Y.) said in his closing remarks, calling the president’s conduct “clearly impeachable.”

Nadler added: “In abusing his office in this manner, and in obstructing the investigation that followed, we know that President Trump has put himself before his country.”

If Trump is impeached, the Senate — currently controlled by Republicans in a 53-47 majority — would hold a trial that’s likely to begin early next year. A two-thirds majority vote is required to remove a president, meaning about 20 GOP lawmakers would need to join all Democratic senators in voting to remove Trump.

This is a developing story. Please check back for updates.