, WASHINGTON, Apr 16 – It is Donald Trump’s worst nightmare: the Republican White House nomination slipping through his fingers at the party convention in Cleveland in July, after dominating the months-long primary race.
Trump’s White House rivals Ted Cruz and John Kasich said Monday they were teaming up to try to block him from an outright victory in Cleveland — if he does not have a majority of delegates, the GOP would find itself in a contested convention.
So what is a contested convention?
Republican delegates designated during the state-by-state primaries and caucuses held from February to June will choose the party’s candidate for president in Cleveland from July 18-21.
To seize the nomination outright, a candidate must reach an absolute majority of the delegates in play.
For the past four decades, the frontrunner has always reached the magic number — which this year is 1,237.
But the strength of resistance to Trump’s candidacy — still challenged by Cruz, a US senator from Texas, and Kasich, the governor of Ohio, as well as the bulk of the Republican establishment — makes it possible that he may fall short.
That would result in what is known as a contested, or brokered convention.
How would the party pick its nominee?
When a candidate has an absolute majority, party delegates at the convention play a purely symbolic role, effectively rubber-stamping the results of the primaries.
But in the alternative scenario — if no contender can claim the crown outright — the nominee is selected through a series of ballots at the convention, in which the delegates acquire a critical influence.
For the first ballot, party rules in all but a handful of cases oblige delegates to back the candidate to whom they were pledged in the primaries.
Even if Trump does not have 1,237 delegates before the convention, a small number of uncommitted delegates could help him win in the first round.
But if no candidate has a majority in the first round, there is automatically a second ballot.
And that is where things start getting interesting.
“The majority of states free their delegates after the first ballot,” explains Josh Putnam, a campaign expert and political science lecturer at the University of Georgia.
That means those delegates could change their votes — and may gravitate towards an alternative candidate.
The rules vary by state, and in Florida, for instance, delegates are only “released” on the fourth ballot. But according to The New York Times, 57 percent of the delegates would be free to change their votes in the second round, and 81 percent would be freed in a third round.
There is no limit on the number of rounds before a candidate earns a majority.
Who are the delegates and how are they chosen?
According to Republican Party rules, each state and a handful of territories send a certain number of delegates to the convention to elect the nominee.
Over the course of the primaries, each candidate amasses delegates. The rules for choosing these vary from state to state.
Delegates are chosen in local party conventions held throughout the months-long process.
In nearly three quarters of states, they are selected without input from the candidates themselves, according to Ben Ginsberg, a former Republican National Committee lawyer.
In some states, like Connecticut and Rhode Island which vote Tuesday, delegates are awarded proportionally to candidates.
Other states have a winner-takes-all system, like Florida, where all 99 delegates went to Trump as the winner of the state primary on March 15.
Given the choice, many delegates may prefer to back another candidate than the one to whom they were pledged.
That is why the Cruz and Kasich teams have been pulling out the stops to position their supporters at the local conventions that pick delegates.
Who could emerge as nominee?
A contested convention could theoretically throw open the 2016 race to candidates other than Trump, Kasich and Cruz.
But the party could set last-minute rules to limit outside candidacies — for example by requiring that the eventual nominee must have taken part in this year’s primaries.
That would rule out the former presidential candidate Mitt Romney, or House Speaker Paul Ryan — both have been put forth as potential “saviors” for a Republican party in disarray.
Has this happened before?
Brokered conventions are rare in modern American politics.
In 1976, no Republican candidate had a majority when incumbent president Gerald Ford faced Ronald Reagan.
After several days of deal-making, Ford won in the first round thanks to support from a small number of uncommitted delegates.
The last time several vote rounds were needed came in 1948, when Thomas Dewey was the eventual candidate. For the Democrats, the last brokered convention was in 1952, with three rounds necessary to pick Adlai Stevenson.