Trump’s constituency is broad, but “there is a group in there who are socially conservative and supporting Trump despite the fact he doesn’t have a pure record on their issues,” said Patrick Murray, director of the Monmouth University Polling Institute, whose survey in Iowa recently found Trump and Carson tied with Cruz lagging behind in third place. “The indication is if those voters fall, they will go to Cruz.”

The Monmouth poll found that 24 percent of Trump’s supporters picked Cruz as their second choice while 20 percent chose Carson. Mike Huckabee, who won the Iowa caucuses in 2008, came in third at 8 percent in terms of Trump backers’ second choice.

“It seems like Cruz … has the spark, and realizes that if Trump falls by wayside, being seen as a friend of Trump is going to be something that serves you well with voters,” said Murray.

Others, however, find the Trump constituency to be more fragmented. David Brady and Douglas Rivers of the Hoover Institution found that the businessman’s supporters’ second choices are as follows: Carson at 13 percent, Carly Fiorina and Jeb Bush at 10 percent, and Cruz at 9 percent. “If his candidacy falters or he quits the race, no single candidate benefits in more than the low double digits,” they wrote in a piece for RCP.

It appears the Cruz team has seen more evidence of the former theory, however.