Historians Ron Radosh and his wife Allis have written an excellent article for The Observer that looks at the contested GOP convention of 1920, where a superior delegate strategy by candidate Warren Harding allowed him to capture the nomination on the tenth ballot.

Harding's campaign manager, Harry Daugherty, developed a plan that would deny the two frontrunners, General Leonard Wood and Frank O. Lowden of Illinois, a majority, while making Harding everone's second or third choice.

How, then, did Mr. Harding get the nomination, proving all the pundits wrong? First, Mr. Harding and his campaign manager, Harry Daugherty, developed a strategy—based on making Mr. Harding everyone’s second or third choice. With that in mind, in addition to not challenging favorite son candidates in their states, Mr. Harding did not say anything bad about those running against him. Like Mr. Kasich today, he purposefully stood above the fray. Instead, Mr. Harding ran a positive and optimistic campaign focusing on how he would address the severe economic and unemployment problems the country was facing after the end of World War One.

Mr. Harding also was running at the time of a major split in the party, between the regular Republicans and the Progressives, who bolted in 1912 and supported T.R.’s Progressive or Bull Moose Party, and only recently had returned to the Republican ranks. Mr. Harding knew that in order to win, he needed the support of both factions, and would have to stand for policies that appealed to both wings. He was successful in bridging that divide.

To win the nomination, a candidate had to receive 493 delegate votes. If that number was split between Mr. Lowden and Mr. Wood, as Mr. Harding assumed it would be, he believed he could get enough delegates to support him as their second or third choice. His campaign manager, Harry Daugherty, saw to it that all the delegates and potential delegates were contacted and asked to consider supporting Mr. Harding if a deadlock occurred. He told the press that he was “getting in touch with the leaders and delegates who are for Wood and Lowden, “being friendly with them. When the convention comes,” he predicted, “these two armies will battle each other to a standstill. When both realize they can’t win…both the armies will remember me and this little headquarters…both sides will then [go] to Harding.”

And that's exactly what happened.  When it became clear that neither side could win a majority, there was Harding offering himself as a compromise candidate.  Despite winning the lowest number of delegates in first ballot voting, his positive, optimistic campaign carried him into the lead on the ninth ballot and allowed him to wrap the nomination up on the tenth.

A few caveats: politics is very different today, as are party conventions.  But a delegate strategy where the candidate becomes a majority's second choice would not be a bad move today.  I don't think that man is Kasich.  But Rubio?  There is a lot of latent support for the Florida senator, and a convention that threatens to drag on forever might turn to him to save the party.

But perhaps the biggest difference between politics today and politics of the 1920s is the idea that delegates were willing to compromise for the sake of the party back then.  I'm not so sure Cruz and Trump supporters are willing to compromise at all.  They would rather watch the world burn than give up on their candidate.

Certainly that's not a universal feeling among those delegates.  But enough of them might feel that way to prevent a compromise that would allow the party to avoid a bloody floor fight that would doom the GOP to a disastrous defeat in November.