Filibuster

Filibuster, also known as talking out a bill, is a tactic of parliamentary procedure. 
History.
The term "filibuster" comes from the French word "flibustier," meaning "pillaging pirate." In terms of parliamentary procedure, the word was not used until the 19th century However, the use of long speeches as a delaying tactic is part of the history of the Roman Senate. For example, Cato the Younger is known for using filibuster tactics to block Julius Caesar's rise to power. 
United States.
In the United States, current rules in the Senate require all Senators to be allowed to deliver a speech for as long as they want. Voting cannot begin until all Senators finish giving their speeches. A filibuster allows a senator to block a bill by speaking on behalf of the bill for too long on purpose so it would not be brought to a vote. To pass a bill, the Senate only needs at least 50 votes (out of 100) in support of the bill. To end a filibuster will require cloture which requires 60 votes (out of 100) in support. A cloture would allow the bill to be voted on because it forces all debates to end. 
To get around the filibuster, the Senate may choose to include a provision of the bill through a reconciliation bill. A reconciliation bill bans filibusters and only requires 50 votes (out of 100) for it to pass. In 2013, the Senate Democrats changed the rules to ban filibusters for confirming the President's nominee for courts other than the Supreme Court. In 2017, Senate Majority Leader Mitch McConnell added Supreme Court nominations to the ban on filibusters in order to confirm Neil Gorsuch (appointed by Donald Trump) to the Supreme Court with only 50 votes. 
Supporters of the filibuster argue it protects the minority from having no say in the bill. However, critics claim it gives the minority too much power by blocking any legislation. 
In 2021, the Democratic Party introduced legislation that would eliminate the filibuster that could be passed with only a majority vote. However, Democratic senators Joe Manchin and Kyrsten Sinema said they are opposed to modifying the filibuster.