US legislators voted on Wednesday in favour of narrow reforms to a loosely worded 135-year-old law that former president Donald Trump tried to exploit to overturn his presidential election defeat.
It comes less than 50 days before the US midterm elections that will decide which party controls Congress.
There has been a sharp rise in the number of candidates who refuse to accept the 2020 results, sparking fears for the health of US democracy.
After losing to Democrat Joe Biden, the Trump campaign tried to take advantage of ambiguities in the 1887 Electoral Count Act in a failed bid to have then-vice president Mike Pence block certification of the results.
Joe Biden pushes for US voting rights law in Atlanta
The Presidential Election Reform Act tightens the wording of the ECA — which lays out how the state-by-state Electoral College results are tallied — on the vice president's role and on how many politicians are required to object to a state's election results.
The controversy was at the heart of the 2021 US Capitol insurrection, and there is cross-party enthusiasm in both chambers of Congress to ensure there is no repeat of the violence that left scores of police with injuries and was linked to five deaths.
"This bill will prevent Congress from illegally choosing the president itself," said Republican Liz Cheney, who co-wrote the text and has a leading role in the congressional investigation into Mr Trump's actions before and during last year's violence.
The House bill passed by 229-203, with eight other Republicans crossing the aisle.
But it looks unlikely to prevail in negotiations to merge the legislation with a narrower Senate version that appears already to have the Republican support required to get to Mr Biden's desk.
Neither effort is as comprehensive as the Freedom to Vote Act and John Lewis Voting Rights Advancement Act, which fell to a Republican blockade in the Senate.
Progressive Democrats see the latest drive as a poor substitute for those bills, which took aim at restrictive voting laws being introduced in Republican-led states across the country.
