A brokered convention is very unlikely. But the possibility that the Republican nomination will come down to a convention floor fight keeps coming up. Former House Majority leader Dick Armey (R-Texas) is the latest to suggest it; Rush Limbaugh and Joe Scarborough say conservatives are chattering about the idea.

If it did happen, here’s how it would work.

At each caucus or primary, voters are actually choosing delegates to the national convention who have pledged themselves to a candidate. At the Republican convention in Tampa, the 2,286 delegates will vote.

In recent history, conventions are basically a meaningless tradition in which only one ballot is held, choosing a nominee that has already been decided in the primaries.

But in theory, former Massachusetts governor Mitt Romney could fail to garner the 1,144 delegates needed to assure victory. Right now he only has 37 delegates, including party officials who get an automatic vote. Former House speaker Newt Gingrich could refuse to drop out (he says he’s in for the long haul).

If there was a convention-floor fight, multiple ballots would be taken until one candidate got a majority. Romney’s supporters would have to attempt to wrangle delegates away from other candidates. Other candidates could also attempt to consolidate support. A “dark horse” candidate (for example, former Florida governor Jeb Bush) could emerge late in the primary process, or even at the convention itself, and still win.

There are 412 unpledged delegates, with an additional 65 that can be unbound depending on conventions in Minnesota and Louisiana, says political scientist Josh Putnam.

That includes both “automatic” delegates (similar to the Democratic “superdelegates” who got so much attention in 2008 but fewer in number) and delegates from nonbinding caucus states. Their votes are basically up for grabs outside the state-by-state process.

Very few of the automatic delegates have committed to a candidate (those that have tend to favor Romney.) In the event of a tie between Romney and Gingrich, these delegates could the deciding votes. It the delegate share is divided between three or four candidates, it would get more complicated.

Brokered conventions used to be common. From the 1830s to 1950s, party delegates came to the conventions unsure of their choices. There would be multiple ballots — not unlike a caucus — between which delegates could change their votes. Polls of delegates were taken to see where they stood.

The last brokered Republican convention was in 1948, when New York Gov. Thomas Dewey came out on top after three ballots.

The 1976 Republican primary came close, when President Gerald Ford only won a narrow victory over Ronald Reagan on the first convention ballot. So did the 1984 Democratic primary, when Vice President Walter Mondale needed superdelegates’ votes to beat Gary Hart at the convention.

But despite those close calls, there has not been a brokered convention in the past 50 years. Television is a major factor. Party members did not want to engage in angry brawls with the public watching.

The delegates are also no longer expected to have their own opinions on the race, nor are they controlled by party bosses.

“The delegates are slated by the campaigns, these are not necessarily party leaders or anything like that,” said Jonathan Bernstein, a political scientist who blogs about American politics. He argues that given the lack of political powerbrokers who would pressure delegates into voting one way or another, a brokered convention should really be called a “deadlocked convention.”

If no candidate has a majority, “It’s totally unclear what the delegates will do,” said Bernstein. “They might love their candidate so much that they would do whatever the candidate says, they might not. The result could very well be chaos.”