With the issue of voting rights and election reform resurfacing in the aftermath of the Jan. 6 Capitol attack anniversary and ahead of the 2022 midterm elections, Democrats are looking to change a Senate rule in order to pass legislation they believe is critical to preserving American democracy.

Republicans, meanwhile, have warned that even a single exception to the Senate’s 60-vote threshold to advance legislation – a rule known as the filibuster – would be dangerous to democracy and the rights of the minority party.

Senate Republicans used the filibuster to stymie two important voting bills, the Freedom to Vote Act and the John Lewis Voting Rights Advancement Act — a top priority for Democrats and President Joe Biden remains stalled in an evenly split 50-50 Senate.

Over the years, both parties have flirted with the idea of abolishing the filibuster in order to make it easier for the majority party to achieve its goals. Here’s everything you need to know about the filibuster:

The filibuster is a Senate procedural rule from the nineteenth century that allows any senator to obstruct or delay action on a bill or other matter by extending debate.

While a simple majority of 51 votes is required for a final vote in the Senate, a supermajority, or 60 votes, is required to begin or end debate on legislation so that it can proceed to a final vote.

As a result, even if a party has a slim majority in the Senate, it still requires a supermajority to move legislation forward — a tall task for a hyper-partisan Washington.

The filibuster is not used in the House of Representatives. Instead, a simple majority can put an end to the debate.

Senate rules allow debate to continue indefinitely until three-fifths of the chamber votes to end the filibuster, or 60 senators out of 100.

In recent decades, simply indicating a senator’s intent to filibuster a piece of legislation has been enough to halt action on the bill. Leaders may drop the issue from consideration in the meantime, knowing that the legislation lacks the support of 60 senators.

According to the Brennan Center for Justice, there have been over 2,000 filibusters since 1917. Almost half have occurred in the last 12 years. One option is to “go nuclear,” which is when senators override an existing rule, such as the number of votes required to end debate. This is usually accomplished by lowering the number of votes required to end a filibuster to 50.

A few years later, in 2017, then-Senate Majority Leader Mitch McConnell, R-Ky., abolished the filibuster for Supreme Court nominees, allowing then-President Donald Trump’s first nominee to be confirmed.

Many fear that if the filibuster is abolished, the ruling party will be able to govern without regard for the minority, establishing a dangerous precedent for a deliberative democracy.

Over the last 50 years, the filibuster has been increasingly used to kill major legislation. With Biden’s agenda stalled, Democrats are calling for a break in order to pass voting rights legislation. According to the Brennan Center for Justice, at least 19 states passed 34 laws restricting voting access in the last year.

If the threshold for ending debate on a bill is reduced to 50 votes, for example, Democrats could end debate on their voting reform bill and eventually move to a final vote, with Vice President Kamala Harris acting as a tie-breaking vote in a 50-50 Senate to pass the legislation. In addition, as Senate President, Harris would play a key role in any potential rule change. She would be expected to sit in the chair and oversee any rule changes.