Senate Majority Leader Chuck Schumer postponed votes on two voting rights bills late Thursday, delaying a debate over the chamber’s rules that will determine the fate of election reforms that the party sees as critical to protecting U.S. democracy.

The New York Democrat said the bill would not be considered until Tuesday because of “the circumstances surrounding Covid and another potentially hazardous winter storm” approaching Washington, D.C. Sen. Brian Schatz, D-Hawaii, announced a positive Covid-19 test on Thursday. Democrats will lack a simple majority until he can return to the Senate, which is evenly divided.

Republicans intend to oppose the Freedom to Vote Act and the John Lewis Voting Rights Advancement Act. If the bills fail, Democrats intend to look into ways to avoid the filibuster and pass the legislation with a simple majority.

The plan appears to be doomed. While all Senate Democrats have signed on to the elections legislation, at least two — West Virginia’s Joe Manchin and Arizona’s Kyrsten Sinema — have stated that they will not support the filibuster changes required to pass it. Currently, Democrats require at least ten Republicans to pass most legislation.

If the two centrist senators stand firm on rule changes, it appears that Democrats will be unable to pass a series of reforms that they see as critical to protecting ballot access. The bills’ provisions would expand early and mail-in voting, make automatic voter registration the national standard, make Election Day a national holiday, and restore parts of the Voting Rights Act of 1965 that had been struck down by the Supreme Court.

It is unclear how Democrats will proceed if the filibuster is not repealed. Some Republicans have expressed interest in amending the Electoral Count Act of 1887 to make it more difficult for local officials to tamper with election results.

Last year, certain Republican officials supported former President Donald Trump’s push to overturn swing-state presidential election results based on false conspiracy theories that widespread fraud caused his loss to President Joe Biden.

Many Democrats have criticized vote-counting reforms as insufficient unless changes are made to allow more people to vote in the first place. However, making it more difficult to overturn results may become one of their only options if their preferred bills fail.

Democrats tried and failed to pass election legislation several times in the last year, as Trump’s election lies fueled the Jan. 6 Capitol attack and contributed to the passage of restrictive voting laws in states such as Texas and Georgia. A year after a pro-Trump mob stormed the Capitol while Congress was counting Biden’s victory, the president depicted a democracy under attack in a pair of speeches this month, urging the Senate to change its rules to protect elections.

Biden spent more than an hour with Manchin and Sinema on Thursday evening. According to a White House official, they had “a candid and respectful exchange of views about voting rights.”

Earlier in the day, the president met with Senate Democrats and sounded pessimistic about his party’s chances of passing voting rights legislation.

Senate realities have indicated that the bills will fail. Democrats, on the other hand, wanted to show their voters that they were making an effort to pass reforms after Trump attempted to overturn the election and state legislatures passed laws that could disproportionately harm voters of color.

Republicans have claimed that the Democratic bills go too far. They claim that the plans would give the federal government undue influence over state elections. Congress has passed legislation to protect voting rights in the past, most notably the Voting Rights Act that Democrats aim to restore.

The GOP has also cast exceptions to the filibuster as a fundamental change to the Senate’s function that would make lawmakers less likely to find consensus.

As he stared down the voting rights legislation’s likely failure, Biden pledged to keep trying to protect ballot access.