Members of the US House of Representatives have voted to censure Democratic representative Jamaal Bowman for triggering a fire alarm in one of the US Capitol office buildings when the chamber was in session. The Republican censure resolution passed with some Democratic votes but most Democrats stood by Bowman in opposition of an effort they said lacked credibility and integrity. The prominent progressive becomes the third Democratic House member to be admonished this year through the censure process, which is a punishment one step below expulsion from the House. "It's painfully obvious to myself, my colleagues and the American people that the Republican Party is deeply unserious and unable to legislate," Bowman said on Wednesday as he defended himself during floor debate. "Their censure resolution against me today continues to demonstrate their inability to govern and serve the American people." The 214-191 vote to censure Bowman caps nearly a year of chaos and retribution in the House of Representatives. Since January, the chamber has had the removal of a member from a committee assignment, the first ouster of a Speaker in history and, last week, the expulsion of a lawmaker for only the third time since the Civil War. Representative Lisa McClain, who introduced the censure resolution, said Bowman pulled the alarm in September to "cause chaos and the stop the House from doing its business" as lawmakers scrambled to pass a bill to fund the government before a shutdown deadline. "It is reprehensible that a member of Congress would go to such lengths to prevent House Republicans from bringing forth a vote to keep the government operating and Americans receiving their paychecks," McClain said in a statement. Bowman pleaded guilty in October to a misdemeanour count for the incident, which took place in the Cannon House Office Building. He agreed to pay a $US1,000 ($A1,520) fine and serve three months of probation, after which the false fire alarm charge is expected to be dismissed from his record under an agreement with prosecutors. The fire alarm prompted a building-wide evacuation when the House was in session and staffers were working in the building. The building was reopened an hour later after Capitol police determined there was no threat. Bowman apologised and said that at the time he was trying to get through a door that was usually open but was closed that day because it was the weekend. The vote is the latest example of how the chamber has begun to deploy punishments like censure, long viewed as a punishment of last resort, routinely and often in strikingly partisan ways. "Under Republican control, this chamber has become a place where trivial issues get debated passionately and important ones not at all," Democrat representative Jim McGovern said during floor debate. Australian Associated Press