After nearly six months of watching Republicans relentlessly make it harder to vote in the US, Democrats suffered a major blow on Tuesday after GOP senators used a legislative maneuver to halt a sweeping voting rights and ethics bill.

The vote doesn’t kill the bill, but it marks one of the most significant setbacks for Democrats in Joe Biden’s presidency so far. Democrats heralded the legislation as their No 1 priority, even knowing they were unlikely to get any Republican votes for it. The bill would amount to the most significant expansion of the right to vote in a generation, requiring early voting and automatic and same-day registration, while prohibiting excessive manipulation of electoral district boundaries, a process often called gerrymandering.

Sign up for the Guardian's Fight to Vote newsletter

It wasn’t an unexpected result. Democrats control only 50 seats in the Senate and a procedural rule, the filibuster, blocks most legislation from proceeding to a full debate on the floor unless it has 60 votes. A handful of Democratic senators, most notably Joe Manchin of West Virginia and Kyrsten Sinema of Arizona, support keeping the filibuster in place, saying it helps ensure the minority party has a say. But while the rule remains, Democrats have virtually no chance of passing sweeping voting rights legislation.

Democratic senators are now in a quagmire amid escalating concerns that Democrats, who control both Congress and the White House, might not be able to use their power to stop what many experts see as openly anti-democratic efforts by Republicans across the country to make it harder to vote after an election in which there was record turnout, including surges among Black, Asian American and Hispanic voters.

Republicans have used partisan majorities in statehouses across the US to pass these measures, even as they have accused Democrats of acting with partisan intent to pass voting reforms.