It was a newsy day in the Republican presidential nomination race: Texas Gov. Rick Perry announced his candidacy, and Michele Bachmann edged out Ron Paul to win the Ames Straw Poll in Iowa. Combined, those events set the race as a matchup between Perry and Mitt Romney.

The candidate who had the most on the line at Ames, by far, was Tim Pawlenty. Six months ago, Pawlenty appeared to be on his way to having an excellent chance at the nomination. Since then, virtually nothing has gone right for him.

Ames is an unusually visible part of the invisible primary; it matters to the extent that party actors who are trying to choose a candidate take it seriously as a signal of candidate viability. If Pawlenty were doing well otherwise, the respectable but distant third-place finish at Ames wouldn’t matter much at all. Since by all accounts he isn’t, there’s every possibility that Ames will kill his candidacy for good. It’s hard to believe that there are a lot of Republicans at this point who want to invest resources in Pawlenty, and without that he might as well pack it in.

Why spend so much time on a candidate whom many have written off a long time ago? Because Pawlenty could have won. And if he’s done, that really leaves only two viable candidates in the race: Rick Perry and Mitt Romney, both of whom ducked the fun in Iowa today.

What of the winners at Ames? Michele Bachmann continues to prove that she can appeal to Tea Partyers and other intense conservatives. I remain unconvinced, however, that a three-term member of the House of Representatives is a serious threat to win the presidential nomination. She’s done an excellent job of consolidating her potential support, and there’s every possibility that she’s going to make plenty of noise next year when the real voting starts. However, no one with similar credentials or similarly on an ideological fringe has ever come close to winning a nomination, certainly not since the modern process began in the 1970s.

And Ron Paul’s ceiling almost certainly remains about where it was four years ago. Republicans may not be quite as hawkish as they were in the heyday of George W. Bush and the neoconservatives, but Paul’s foreign policy views will still draw a veto from several organized groups in the party.

So if Pawlenty is done, we’re really down to Perry and Romney. Sarah Palin’s chances, if she does decide to make a proper run, continue to wane; it’s unlikely that anyone else could jump in this late and really have a chance. Remember, Perry announced today, but he’s been running for some time. Perhaps Jeb Bush could still do it, but I think his window is at best closing rapidly. No other potential candidate could do it.

And so now we start finding out whether the reality of a Rick Perry campaign is as formidable as the idea of one. Kevin Drum makes the argument against it today, but I really think it comes down to one thing: Until a candidate goes through the process, it’s never possible to know how he or she will do at it.

Overall? Intrade has Perry and Romney combined at a bit over 60 percent chance of winning. I’d say that’s way, way, low. In my view, the odds of one of them winning the GOP nomination are probably around 90 percent, give or take a bit.