Democrats in the Texas legislature have left their state en masse in an effort to prevent Republicans there from passing a law to tighten voting rules.
The move will temporarily paralyse the state's House of Representatives, which requires at least two-thirds of lawmakers be present for a vote.
At least 50 House Democrats boarded two private jets from Austin to Washington DC on Monday.
The move comes amid a wave of voting restrictions in Republican-led states.
An important first vote on the sweeping voting legislation proposed by Texas Republicans was planned for later this week.
The bill would outlaw 24-hour polling places and drive-through voting, ban ballot drop boxes and expand the authority of partisan poll watchers.
The House lawmakers took off on Monday afternoon - the first time since 2003 that state Democrats have left Texas to break quorum.
Texas Democrats said they would not return until the 30-day special session had ended next month.
Top Texas Democrat Chris Turner said in a statement: "We are now taking the fight to our nation's Capitol. We are living on borrowed time in Texas."
The fleeing lawmakers do so under threat of arrest. Under Texas law, legislators can be legally compelled to return to the state capital in Austin.
The Democrats' action also hopes to put pressure on Washington lawmakers and US President Joe Biden, who is facing calls from activists to do more at the federal level to protect voting rights. Mr Biden, a Democrat, is scheduled to deliver a major speech on the issue on Tuesday, in Philadelphia.
This marks the second time in six weeks that Texas Democrats have used a walk-out as a delay tactic.
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