On paper, the Constitution mandates that “the House of Representatives shall [choose] their speaker.” In practice, though, this simple requirement has sparked some of the most colorful and controversial episodes in congressional history.

The looming showdown between incumbent Speaker John Boehner and some Republican critics could write the next chapter.

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By law, the House must elect a presiding officer before taking up any new business. On Tuesday, the 114th Congress will choose a speaker, the highest legislative office in the nation and second in line of presidential succession, according to the Constitution.

The election of a House speaker requires that one candidate receive an absolute majority–more than half the votes cast.

If a majority fails to choose a winner, the House clerk simply calls another vote until the position is filled.

The law leaves the contest wide open otherwise. The Constitution doesn’t even require the speaker come from the House of Representatives or elected office at all. In 2013, unelected former Secretary of State Colin Powell and former Rep. Allen West received votes.

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Generally, the nominee from the majority party gets the procedural nod on the first ballot. However, certain notable exceptions have shaped American history and the office.

In 1856, as sectional strife threatened the union, the issue of slavery sparked the longest election for speaker in American history. Presented with multiple candidates, the 34th Congress bickered over the position for more than two months.

Finally on the 133rd ballot, the House elected the first Republican speaker, Nathanial Banks of Massachusetts.

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The last time Congress failed to immediately elect a speaker of the House was 1923. Still chafing from the heavy-handed speakership of Joe Cannon, the progressive wing of the Republican Party forced nine ballots before allowing Frederick Gillet to become speaker in exchange for policy compromises.

Republicans unsatisfied with established leadership could follow suit Tuesday.

Twenty-nine Republican votes are necessary to block Boehner from returning as speaker for the 114th Congress. So far, 10 have declared their opposition, including two Republicans—Reps. Louie Gohmert of Texas and Ted Yoho of Florida—who stepped forward as alternatives.

From 1913 to 2013, from the swearing in of the 63rd to 113th Congresses, 32 candidates other than the party’s official choice have received votes. Here are some of the most notable:

1913: Rep. Victor Murdock of Kansas (Progressive Party)

A journalist turned progressive politician, Murdock was nominated in 1913 and received the most votes of any outside candidate in the 20th century, 18. He later served as a war correspondent in 1916 and was a member of the Federal Trade Commission from 1917 to 1924.

1917: Rep. Fredrick H. Gillett of Massachusetts (Republican)

A mild-mannered man, Gillett only received two votes when he was nominated in 1917. Two years later, his easy-going nature earned him the office when he was billed as an unassertive leadership alternative. A reporter later recalled that Gillett avoided drinking coffee in the morning “for fear it’d keep him awake.”

1925: Rep. Henry Allan Cooper of Wisconsin (Republican)

Cooper was nominated three times in 1913, 1923 and finally 1925. He holds the record for the most speaker nominations during the Progressive Era.

1997: Rep. James Leach of Iowa (Republican)

Billed as an alternative to then-Speaker Newt Gingrich, Leach was the first outside candidate nominated to challenge an incumbent since Franklin Roosevelt was president. Leach didn’t even vote for himself.

2001: Rep. John P. Murtha of Pennsylvania (Democrat)

The government named Murtha an “unindicted co-conspirator” during the ABSCAM investigation, the sting operation that later inspired the movie “American Hustle.” He was unsuccessfully nominated for speaker in 2001, 2003 and 2005.

2011: Rep. Heath Shuler of North Carolina (Democrat)

The former NFL quarterback and Heisman Trophy runner-up represented North Carolina’s 11th congressional district from 2007 to 2013. As a member of the Blue Dog Coalition, he was viewed by Democrats as an alternative to Minority Leader Nancy Pelosi, D-Calif. Shuler received 11 votes.

2013: Colin Powell (Republican)

A former White House national security adviser, chairman of the Joint Chiefs and President George W. Bush’s secretary of State, Colin Powell has never held elected office. He received one vote in 2013 nevertheless.

2013: Rep. Jim Jordan of Ohio (Republican)

Jordan’s chairmanship of the Republican Study Committee gave him a platform to speak on behalf of House conservatives. Unsurprisingly, Jordan voted for Boehner instead.

2013: Allen West (Republican)

Allen West had just left his Florida congressional seat in 2013 when he received two votes for speaker of the House.