Yet another debate review, this time with convention rules!

Man, if the GOP establishment players had gotten their act together even as recently as two months ago Trump would be somewhere in the middle of the pack and dropping.
Rubio and Cruz made a fairly impressive coordinated attack on Trump tonight, with Rubio getting the lions share of the credit, meanwhile, Kasich and Carson where virtually ignored, as they should be. It was an interesting look at what might have been, if there were any competent people on the campaign staffs of the candidates.

Far too little too late though, Trump will secure enough delegates that he can be the nominee, the only question is can Rubio or Cruz close the gap enough that the RNC can get away with changing rules to screw Trump out of the nomination. It's totally possible, the thing about the convention rules is they can be changed, you know who votes to change them? The delegates, on the face of it this might seem impossible for Trump to lose, if he has the most delegates than they obviously wouldn't vote for any rule change that screws him, not actually so.
See the delegates are only bound to vote for Trump on the actual nomination process, they are completely allowed to vote on rules changes that can fuck Trump, and probably somewhere around half of them kinda don't like the guy and just might.
They could change the rules to unbind the delegates and have a new vote at the RNC, they could decide that Trump is not a suitable candidate and remove him from consideration, or virtually any other thing you can think of, the candidate selection process is not really regulated by law so almost anything is possible.

But not likely, a ratfucking of Trump would probably be worse for the GOP than just running him, especially if he decides to go it with another party or run independent, now those have some obstacles too, namely it is really hard for an independent to meet requirements to get on the ballots in many states, he would have had to have been gathering signatures basically last year for that to work, but the Libertarian convention is after the RNC, and it is entirely plausible to say he would try to get that nomination.
But like I said, unlikely, odds are he'll come out of the convention the nominee, and then the real fun begins.

Adding to the pile of evidence that the candidates are a bunch of incompetent buffoons, no one has done opposition research on Donald Trump, at all, and the GOP is kinda scrambling now to try to pull something together, they research on Trump these days consists of news clippings and records of his public appearances and documents he has made available himself. But real opposition research involves deep background information, digging into documents and records that are not something the average citizen has access to, interviews with background figures in his life, tracking money movement, and so on. They haven't done any of this, Trump has set the narrative, and controlled public perception of himself completely so far, and it honestly isn't going to change before the RNC

But one group realized about eight months ago that they would need to treat this seriously; the Democrats have been doing their research, and per party insiders there is a lot of information there that hasn't seen the light of day... yet. The Democratic candidate will be able to bring out fresh and heretofore unseen issues to use in attacks on Trump and it's going to be amazing. The only way to bring down Trump is to attack, to mock and to attack again, hopefully while mocking, the man is thin-skinned and has so much to mock even in the last few months, he reacts extraordinarily powerfully when people make fun of him, see the White House Correspondents Dinner of a few years ago, when Obama  decided that he would spend the day making fun of the Donald. It's gonna be a whole campaign of that and it's gonna be fun.