I must credit the attorney, author, editor, and conservative talk show host, Mark R. Levin, with many of the following historical insights that are relevant to this currently hot political topic.
The first Republican presidential convention took place in 1856. (The Republican Party had been founded in 1854, but that was not a presidential election year.) John C. Fremont was the party's first nominee, and, although he did not win, he was a strong enough third party candidate to prove that the GOP had a future (although it was not called the "GOP" until after the Civil War). In 1860, the Republican nominee was Abraham Lincoln, a one-term congressman who had run for the U.S. Senate but had no real executive job experience. (So, according to today's common prejudices about the necessary experience a presidential candidate must have, a man regarded as one of the country's best presidents would now be widely regarded as unqualified.) In the general election, Lincoln ultimately would benefit from the fact that the slavery issue had torn the Democratic Party in two, so that Lincoln ran against at least two major candidates and won with a plurality rather than a majority.
Lincoln was no shoo-in for the Republican nomination. When Republicans arrived at their convention in Chicago, William H. Seward (who is now best remembered for his decision, as Secretary of State in 1867, to add Alaska to the territories of the United States) had 45 percent of the delegates. Lincoln had some delegates from Illinois, his home state, and not much else. Here is where the story illuminates our contemporary controversy. Rule 16 of the Republican convention rules states that the candidate for president who hopes to become the party's nominee must have a majority of the delegates committed to him. Forty-five percent is obviously short of a majority, so Lincoln was able to benefit from the lack of a consensus in Seward's favor. In fact, Lincoln was able to pull some clever tricks to seat delegates in place of Seward's official delegates. He was helped, in part, by the existence of a "Stop Seward Movement" that was willing to entertain "anybody but Seward." On the third ballot, Lincoln won a majority of votes and became the nominee.
Today, Rule 16 still exists. (It occurs to me as likely, though I do not know this for a fact, that this rule is numbered "16" precisely because it was the sixteenth Republican Party Convention rule when the rules were originally being written. Since it was in effect in 1860, that makes sense.) Under the current system, the number of delegates that a candidate at the Republican Convention of 2016 must have in order to have a majority and become the nominee is 1,237 (50 percent + 1 of 2472). This means that the would-be nominee must have that number of delegates on day one of the convention if he or she hopes to become the nominee on the first ballot. As of (March 29, 2016), the front runner in the Republican race has 739 delegates, which is far short of 1,237. There are about twenty more primaries to go; so, he could pick up the needed delegates to make the required threshold; however, as Jim Geraghty of National Review points out, so far, the front runner has been getting about 46 percent of the delegates, and, if he only gets 46 percent of the remaining delegates, he will be at 1,170 delegates or 67 delegates short of the necessary 1,237. According to the “Rules Are Rules, and Tough Twinkies If You Don’t Have Enough Delegates” argument, that means the front runner will not have enough votes to win the nomination on the first ballot, and everybody is in for a floor fight and more than one ballot. (That is called a contested convention, which is different from a brokered convention, which is a kind of contested convention where much is decided in backrooms rather than only on the floor of the convention.)
Even if the front runner does not have 1,237 delegates at the outset of the convention, he is not necessarily in trouble. Delegates are given different instructions by their states, but by the third ballot, most of them are free to vote for whomever they please from among the qualified candidates, even if it is not the person to whom they were originally committed. Enough delegates committed to other candidates could switch to the front runner to give him 1,237. (All could also go to another candidate, which is what happened in 1860.) The wrinkle comes when we consider what it means to be a qualified candidate. Traditionally, the candidate could be anyone, regardless of how many delegates they had coming into the convention. (Possibly even zero.) However, because of a rule rewritten in 2012 in order to prevent a candidate like Ron Paul (R-Tex.) from becoming the nominee despite not having many delegates, the universe of qualified candidates this years could be exceedingly small. Rule 40(b) (normally called Rule 40 for short) originally said that in order to be considered a qualified candidate, one must have won a plurality of delegates in five states. The text was changed four years ago from "plurality" to "majority" and from five states to eight. This would mean that the candidate either won in eight states where the winner took all of the delegates, or else, that in each of eight states where the delegates were distributed proportionally, he won the majority. (Or a mixture of these categories.)
The astute reader will remember that, in the early primaries and caucuses of 2016, there were as many as sixteen or seventeen candidates on the ballot, and, therefore, it was not unusual for a candidate to win the election without winning a majority of the delegates from that state, and even by as late as March 19, the majority of primaries and caucuses had not been winner-take-all contests. [As of March 29, the front runner has a majority of delegates from eleven primaries and caucuses. He has made the hurdle. His chief opponent, who currently has 465 delegates, has won a majority in only five contests, but his winning three more seems possible and even likely.] For purposes of Rule 40, winning the majority of delegates in one of the territories counts toward each candidate's majority-in-eight-states goal. This is why the candidates have taken what would otherwise seem an eccentric interest in such contests as Puerto Rico, Guam and the Northern Mariana Islands where no one can vote in the general election.
Rule 40 has been under attack because, theoretically, it could prevent anyone at all from becoming the nominee, which is obviously absurd. If no candidate wins majorities in eight states or territories before the convention, Rule 40 would have the effect of rendering the front runner unqualified even if he did have 1,237 delegates. Unlikely, yes, but just possible. Further, it is possible and now even likely, that the front runner will have fewer than 1,237 delegates but have a majority in eight states. If the second runner has not won majorities of delegates in eight states by the convention, he will not be qualified to run on a second or third ballot. Even though, on the opening day of the convention, the front runner will be unhappy if he is short of the required 1,237 delegates, having made the eight-state threshold, he might turn around and become an advocate for not changing Rule 40 because it benefits him now. Rule 40 could exclude every other possible candidate, not just the second-place candidate. If he has not won a majority of the delegates from eight states, then neither will anyone else have. Then no one will be able to oppose the front runner even if he does not have a majority on the first ballot, and delegates will have no other qualified candidate to vote for on the second and subsequent ballots.
In other words, if Rule 40(b) remains as it is currently written, there are four theoretical possibilities:
2) Only the front runner will be qualified.
4) Only the front and second runners will be qualified.
In situation number one, everyone would have been working themselves into a righteous rage even before the convention, and the repeal of Rule 40 would be absolutely necessary, throwing the convention wide open in the process. In situation number two, the second runner as well as the establishment party regulars, who dislike both the front and second runners, will be fuming. Most likely they will want to repeal Rule 40, but doing so would be transparently self-serving. The third situation cannot occur this election cycle, and I include it only because, under the vicissitudes of Rule 40, it could theoretically happen in the future, if Rule 40 is not repealed. In the last situation, the establishment will be jumping up and down with fury while the factions for the two qualified candidates will have relatively more nuanced feelings depending on what related circumstances seem most advantageous to each of them. Most likely, the second candidate and his supporters will be happier than the front runner and his supporters, especially if the front runner does not have the 1,237 delegates needed to win on the first ballot. The second runner would then be in a position to win over delegates on the second or third ballots, even seducing those initially committed to the front runner.
From the perspective of the establishment, the best move would be to remove the impediment of Rule 40, which, ironically, they were responsible for creating four years ago when it benefited them. The time to remove or rewrite the offending rule might well be before the first ballot, although I could be mistaken about that. If the same floor delegates who will be casting votes for the nominee are asked to vote on the repeal of the 2012 change to Rule 40 or repeal 40(b) entirely, you can see how the issue will not be academic to the delegates. Each will see his or her interest in which way they vote. It will affect who they can vote for on subsequent ballots. Changing Rule 40 will potentially hurt the two leading candidates, because it could allow anyone to be nominated in addition to the leading candidates. Without Rule 40(b), a person who has not even been in the race could be nominated in the convention and awarded the requisite 1,237 votes on the third ballot. (Such a stealth candidate is called a "dark horse.")
There is a question I wish I could answer but can't. What happens, under Rule 40, to the delegates committed to those candidates who have dropped out of the race before the convention? This much is fairly clear: Under the old Rule 16, the candidate with the third highest delegate total, who in this case has 166 delegates, could urge them to vote for one of the still qualified candidates on the second or third ballot. Of course, even without his urging, once their commitment to the candidate who won them in the primary or caucus expires, the delegates are released from their commitment and are free to vote for another candidate of their choice. But I presume that this process does not apply to Rule 40. For example, the third-place candidate, who has already dropped out, won the majority of delegates from Puerto Rico. Suppose that the second-place candidate had won a majority of delegates in only seven states. If he wanted to, could the third-place candidate award his delegates from Puerto Rico, or could the delegates from Puerto Rico declare themselves, in favor of the second-place candidate, thereby giving him a majority of delegates in eight states? I doubt that the eight-state rule is transferable in this way, but it might be.
In conclusion, the Republican Convention of 2016 could be unsettlingly interesting and even exciting. Not adding the least to the cauldron of chaos will be the fact that participants will create much Sturm und Drang through both legitimate and illegitimate complaints. Ignorance of the rules is already causing a lot of nonsense to be uttered on news programs, even by presenters on the big networks who get mixed up in trying to explain it to their viewers. (Levin screened an attempted explanation of the GOP convention rules on NBC News and then commented on all the mistakes and contradictions that were made in the report.)
The supporters of the front runner seem to be upset already that the nomination might be won by someone who arrives with fewer delegates. This, however, is in accord with the party rules as established before 1860. The nominee must have the most delegates on the final ballot, not the most popular votes before the convention balloting. This is not to say that such an outcome will not cause disaffection and even hurt the prospects of the Republicans in the general election. No amount of explanation of the rules will convince the front runner's supporters that the nomination was not stolen from him if he does not get it. Manipulation of Rule 40 will give some credence to their protests. It is an excessively exclusive rule to begin with, but changing it at the last moment because doing so benefits the entrenched old guard who invented it four years ago will certainly cause an explosive controversy.