As Donald Trump steamrolls toward a delegate majority that would give him a first ballot nomination at the Cleveland convention, the possibility still exists that Ted Cruz and John Kasich will win just enough delegates in the remaining primaries and caucuses to deny Trump the nomination outright on the first ballot.

If that were to occur, Trump's fate, and that of the Republican Party, could be decided by about 200 "unbound" delegates – delegates who would arrive in Cleveland not pledged to any candidate.

Many of them are starting to feel the pressure already.

The Hill:

A handful of states and territories — Colorado and North Dakota among them — chose not to hold a vote at all, which means most of their delegates will arrive at the convention free to cast their ballot for any candidate.

And in some states, the delegates who were bound to candidates no longer in the race — such as Jeb Bush and Marco Rubio — are unbound as well.

Trump could still collect the 1,237 delegates needed to win the contest outright and avoid a contested convention. But if he came up short, rivals Ted Cruz and John Kasich could win enough delegates to block Trump from a first-ballot victory.

Speaker Paul Ryan (R-Wis.) last week said a contested convention is becoming more likely.

If Trump is short of 1,237 bound delegates, the unbound delegates could tip the balance in his favor on the first ballot — or they could vote for another candidate and usher in a contested convention, when the vast majority of delegates would be free to pick any candidate.  

Trump has argued if he’s the closest to the magic number, that the delegates should be obligated to give him the nomination.

But that’s not how some unbound delegates see it.

“I’m a purist — the rules shouldn’t be bent for him or anyone else,” said Leslie Tassin Sr., an unbound delegate from Louisiana.

Tassin was previously bound to Rubio, but now that the Florida senator has dropped out of the race, he’ll likely head to the convention able to side with the candidate of his choice.

He’s among a handful of unbound delegates who are known at this point in the process. Most will be selected at state conventions over summer.

State bylaws require House, the unbound delegate in Colorado, to stay neutral in the race until he casts a ballot at the convention in July. Still, he offered some clues as to the factors that will shape his decision.

Like Tassin, House said that if one of the candidates arrives with a strong plurality of delegates, that he wouldn’t feel obligated to push that candidate across the finish line solely by virtue of them coming the closest.

“I’m looking at whether the candidate is a conservative and whether they can win in November,” he said. “I’m voting for the candidate that meets that criteria, period.”

It is likely that if Trump comes up short, he won't be far off – a few dozen delegates at most.  If that's the case, there may be pressure from the party leadership to avoid a bloodbath on the convention floor and work to give Trump the majority he needs on the first ballot.  The fact is, #NeverTrump has failed to get off the ground, and the urge to unite – even behind a potential disaster like Trump – could override many delegates' disgust of the candidate.

A contested convention would doom anyone besides Trump coming out of Cleveland to defeat in the fall.  At least with Trump at the top of the ticket, there's always a chance that Hillary Clinton's campaign could collapse and hand Republicans the White House. 

For many in the GOP, it's not much of a choice.