The resolution, approved by a 232-196 vote, authorises House committees to move forward with formal, public hearings.
The House is investigating whether Trump abused the powers of his office by orchestrating a pressure campaign on Ukraine for domestic, personal political gain.
The House vote was put forward by House Speaker Nancy Pelosi, a Democrat, after a whistle-blower complaint, as well as months of investigative hearings by six House committees targeting the president’s conduct in office and private business dealings.
“This is not any cause for any glee or comfort,” Pelosi said ahead of Thursday’s vote.
She urged fellow members of Congress “to protect the Constitution of the United States. What is at stake in all of this is nothing less than our democracy.”
The eight-page resolution provides for public impeachment hearings by the Intelligence and Judiciary Committees. Consulting lawyers for the committees would conduct questioning of witnesses for extended periods of time instead of five-minute rounds alternating between politicians.
Democrats allege Trump used the leverage of nearly $400 million in security aid to obtain a promise from Ukrainian President Volodymyr Zelenskyy to investigate Joe Biden, a top contender for the Democratic presidential nomination to challenge Trump in 2020, and his son, Hunter, who had served on the board of a Ukrainian gas company. There has been no evidence of wrongdoing by the Bidens.
The Trump administration also sought an investigation of unfounded claims that Ukraine, not Russia, interfered in the the 2016 presidential election, according to testimony.
Trump maintains he did nothing wrong, labelling the impeachment inquiry a “witch-hunt”.
The transition from closed-door testimony to public hearings poses a serious challenge to the president and his defenders who have so far focused on attacking the Democrats’ process.
“The Constitution does not require a floor vote to begin an impeachment inquiry, yet the Republicans have raised the fact that the inquiry has proceeded in the absence of such a resolution as an indication of broader procedural irregularities,” said Melissa Murray, a professor of law at New York University.
“But while Republicans have pointed to perceived procedural irregularities, few have said anything about the underlying substantive concerns animating the inquiry,” Murray told Al Jazeera. “While the floor vote will address concerns about procedure, it will only lend credence to the view that there are serious substantive issues that warrant taking this inquiry to the next level.”