The most likely scenario is still that Romney gets to 1144, and does so without any special shenanigans. However…
A) The calendar is extremely spread out this year. We need to get to the end of March just to be where we were at the beginning of February in 2008. McCain pulled ahead by an uncatchable margin on Super Tuesday in 2008. We won’t have a comparable number of delegates selected for many more weeks now. So the story will be all about how Romney is having trouble closing, even though really we just aren’t as far along in the process yet.
B) So far Romney has been chugging along at a pace that will get him to 1144, but essentially at the last possible moment. We’re talking well into the Spring before he mathematically actually gets the magic number. If he continues at that pace, he will limp into the convention wounded and weak, and challenges may well be possible, causing fun drama. He desperately needs to start winning delegates by a wider margin than he has been, because…
C) While each of the non-Romney’s alone are not doing very well in the delegate race, collectively they just have to do SLIGHTLY better than they have been so far, not to win, but to block Romney from getting to 1144. For this to happen though, the collective non-Romney numbers have to improve… just a tiny bit, but they have to improve. So you have to have Santorum or Gingrich (and Paul) continue to pull delegates and just plain not collapse or run out of steam. Note, at this point some of the few Super Tuesday polls out there show this is a non-Trivial possibility. I’ve seen polls for Georgia (Newt ahead), Ohio (Santorum ahead), and Tennessee (Santorum ahead). And is it hard to believe that Alaska, Idaho, North Dakota, Oklahoma, and Wyoming won’t include a decent delegate haul for Santorum and/or Newt or Paul? (Even if we give Romney Massachussetts, Vermont and Virginia?) There has been light or non-existant polling in those places so far, but I look at them and think it is more than possible that even if Romney “wins” that night, he might do so with a plurality of the delegates rather a decisive over 50% margin. In that case, he’d still be way ahead in delegates, but the other three will have once again succeeded in not letting him get enough to be closing toward 1144 fast enough to get there. (Detailed gaming out of this from FHQ here: http://frontloading.blogspot.com/2012/02/very-rough-estimate-of-republican.html and here: http://frontloading.blogspot.com/2012/02/very-rough-estimate-of-republican_19.html )
D) Given the above, my actual position is what it has been for the last month or so… it will PROBABLY still be Romney, and he will PROBABLY win it outright, but the picture will be a lot clearer after Super Tuesday. We will then have over 35% of the delegates allocated, as opposed to only 11% like we do today. If after Super Tuesday, Romney’s “% of remaining delegates needed to win” number (the one I’ve been posting graphs about regularly) isn’t heading dramatically downward, then it will be very legitimate to start talking about the possibilities of him not getting to 1144. Right now it is fun to think about, but still unlikely. (Let alone the possibility of one of the others actually being on pace to catch up and win, which CAN STILL HAPPEN, but requires a complete Romney collapse.)
E) Unless Romney does a blow out win on Super Tuesday and crushes everybody else, assume that the press will make it out to be a race as long as anybody else is standing at all. Just like they did with Clinton vs Obama, they will pump it up and act like whoever is in 2nd has a chance to catch up long after they really don’t have any real chance of doing so at all. Watch my graphs. If after each contest Romney’s “% to win” goes down, and everybody else’s goes up, then Romney is walking toward the nomination, don’t let any of the hype delude you.
F) OK, lets say that Romney does NOT get to 1144, what then? Well, chances are, as long as he is way ahead in delegates compared to the others, he will probably still be the nominee. Deals will be made. Maybe none of the others actually drop out and throw their support before the convention, they get to get their votes in the roll call and make a big speech, but in the end, the deal is made. One or more of the other guys instruct their delegates to go for Romney on the 2nd or 3rd ballot or whatever in exchange for “something” and Romney gets it. This deal will probably be made before the convention, but worst case scenario, the deal is made by appealing directly to the delegates at the convention, and it ends up being Romney.
G) If the convention is indeed deadlocked, and decides to go with none of the four currently in the race, well, that would just be crazy fun chaos. But the big name candidates that everybody wanted to get in but didn’t will be running away from it as fast as they can. There are good reasons they decided to sit out 2008. Are they going to suddenly decide to want to come into that situation starting way late, starting way from behind, and inheriting a divided and discouraged party? Any reasons they had not to run earlier will be even stronger then. Maybe one could be “called to duty” and reluctantly accept, but would they really be doing anything other than making themselves weaker for 2016? And would a third or fourth tier possibility really be any better to all the assembled delegates? It would be a delightful mess to watch though. Still very unlikely though. There is a path to get to this, but it is very narrow, and all of the above are much more likely…
H) Oh, and of course the only thing even more fun than that kind of chaos, would be the convention not being able to select a candidate even after many ballots, breaking up into multiple conventions selecting different candidates… and splitting the party into two or more pieces. Of course, there are even MORE things that would prevent that, so that is too crazy for even me to contemplate right now. :-)