The longest filibusters in American political history can be measured in hours, not minutes. They were conducted on the floor of the U.S. Senate during charged debates on civil rights, public debt, and the military. In a filibuster, a senator may continue to speak indefinitely to prevent a final vote on the bill. Some read the phone book, cite recipes for fried oysters, or read the Declaration of Independence. So who conducted the longest filibusters? How long did the longest filibusters last? Which important debates were put on hold because of the longest filibusters? Let's take a look.

01 of 05 U.S. Sen. Strom Thurmond The record for the longest filibuster goes to U.S. Sen. Strom Thurmond of South Carolina, who spoke for 24 hours and 18 minutes against the Civil Rights Act of 1957, according to U.S. Senate records. Thurmond began speaking at 8:54 p.m. on Aug. 28 and continued until 9:12 p.m. the following evening, reciting the Declaration of Independence, Bill of Rights, President George Washington's farewell address and other historical documents along the way. Thurmond was not the only lawmaker to filibuster on the issue, however. According to Senate records, teams of senators consumed 57 days filibustering between March 26 and June 19, the day the Civil Rights Act of 1957 passed.

02 of 05 U.S. Sen. Alfonse D'Amato The second longest filibuster was conducted by U.S. Sen. Alfonse D'Amato of New York, who spoke for 23 hours and 30 minutes to stall debate on an important military bill in 1986. D'Amato was incensed about an amendment the bill that would have cut off funding for a jet trainer plane built by a company headquartered in his state, according to published reports.

It was but one of D'Amato's most famous and longest filibusters, though. In 1992, D'Amato held forth on a "gentleman's filibuster" for 15 hours and 14 minutes. He was holding up a pending $27 billion tax bill, and quit his filibuster only after the House of Representatives had adjourned for the year, meaning the legislation had died.

03 of 05 U.S. Sen. Wayne Morse The third longest filibuster in American political history was conducted by U.S. Sen. Wayne Morse of Oregon, described as a "blunt-spoken, iconoclastic populist." Morse was nicknamed "the Tiger of the Senate" because of his tendency to thrive on controversy, and he certainly lived up to that moniker. He was known to speak well into the night on a daily basis when the Senate was in session. Morse spoke for 22 hours and 26 minutes to stall debate on the Tidelands Oil bill in 1953, according to U.S. Senate archives.

04 of 05 U.S. Sen. Robert La Follette Sr. The fourth longest filibuster in American political history was conducted by U.S. Sen. Robert La Follette Sr. of Wisconsin, who spoke for 18 hours and 23 minutes to stall debate in 1908. Senate archives described La Follette as a "fiery progressive senator," a "stem-winding orator and champion of family farmers and the laboring poor." The fourth longest filibuster halted debate on the Aldrich-Vreeland currency bill, which permitted the U.S. Treasury to lend currency to banks during fiscal crises, according to Senate records.

05 of 05 U.S. Sen. William Proxmire The fifth longest filibuster in American political history was conducted by U.S. Sen. William Proxmire of Wisconsin, who spoke for 16 hours and 12 minutes to stall debate on an increase of the public debt ceiling in 1981. Proxmire was concerned about the nation's rising debt level. The bill he wanted to stall action on authorizing a total debt of $1 trillion. Proxmire held forth from 11 a.m. on Sept. 28 through 10:26 a.m. the following day. And though his fiery speech earned him widespread attention, his marathon filibuster came back to haunt him. His detractors in the Senate pointed out taxpayers were paying tens of thousands of dollars to keep the chamber open all night for his speech.