A change put in to the convention last cycle was the requirement that a candidate could only be placed in nomination for the presidency if he or she has a majority of at least 8 states' delegates; this requirement is rule 40(b). According to RNC rules, primaries until March 15 must be run on a proportional basis; the ones after March 15 can be run on a winner-take-all basis. Currently, 27 states have primaries after March 15.
In a broad field as we've seen in 2016, it would at first seem unlikely that, in many of the proportional states, a single candidate will get a majority of delegates from that state. This would in turn seem to make it harder for candidates to get to the needed majority of delegates from 8 states to have their names be nominated for the first floor vote in Cleveland.
But looks can be deceiving. While the first 23 state primaries are officially proportional, state primary rules complicate this proportionality; in many states, it's not necessary to get a majority of the votes in order to get a majority of primary delegates from that state.
Josh Putnam, a political scientist at the University of Georgia, has an invaluable site on the primary process. Putnam provides a breakdown of delegate-apportionment rules for various early states. This breakdown suggests that, in a big field, it might be easier than it seems for a single candidate to claim the majority in an early, proportional primary.
This is partly because some states establish thresholds for candidates to get any delegates: fall below that threshold, and you get no delegates. These thresholds can make it easier for a candidate who has a plurality of votes to get closer to having a majority of delegates.
Take New Hampshire. In order to get any delegates for this state, a candidate has to get at least 10% of the vote. This could potentially cause a number of delegates to be initially unassigned. Going by current RCP polling numbers, 10 candidates, with about 40% of the vote, are under 10% in NH polling. If the vote were held today with that kind of breakdown, 40% of the at-large delegates would be initially unallocated; that 40% would go to whoever had the plurality. Thus, someone who had only a plurality in the upper-20s could end up with a majority of the delegates from NH. Putnam in fact games out a scenario where that happens.
South Carolina, another early primary state, is actually closer to a winner-take-all state. In SC, 29 delegates are assigned statewide (26 at-large, and 3 automatic), and 21 delegates are assigned by congressional district (with 3 delegates per district). The person who wins the statewide vote gets all the statewide delegates. For the congressional-district delegates, the person who wins a plurality in each district gets all 3 of that district's delegates.
I can imagine some mathematical permutations in which a single candidate gets a plurality of the statewide vote while not winning a plurality in any given congressional district, but I would assume that a candidate who has a strong showing across the state would tend to do fairly well on the congressional-district level, too. So a candidate with a plurality could end up sweeping almost all the delegates for that state. In the 2012 SC primary, Newt Gingrich got about 40% of the vote, but he ended up with over 90% of the state's delegates. In any case, the candidate who wins a plurality in SC is going to win a majority of the state's delegates.
Even in more complex primaries, like Georgia's, it's quite possible to see how a candidate who gets plurality of the vote ends up with a majority of the state delegates. The 31 at-large delegates are assigned proportionally to candidates who clear a 20% threshold; if, for example, only one candidate is above 20%, he or she gets all the at-large delegates. 3 automatic delegates go to whoever gets a plurality. Each of the state's 14 congressional districts gets 3 delegates. These 3 delegates are assigned in the following way: 2 go to the winner of that district, and 1 goes to the runner-up. This means that, if the candidate who wins the state's overall vote runs fairly well across the state as a whole, he or she could easily end up racking up most of the state's congressional-district delegates and win a majority of the state's delegates.
There are at least a couple takeaways from all this:
- It's easier than it seems for candidates to get a majority of a state's delegates even in proportional primaries. This means that it could be easier for candidates to win majorities in 8 states in order to get their names placed in nomination on the floor in Cleveland.
- In a big field, a candidate with a plurality who runs well in a variety of states could conceivably leave these states with a majority of the delegates and be in a good position once the winner-take-all states begin in the middle of March. And, if a candidate enters Cleveland with a clear majority of delegates, there will be no brokered convention.