My colleague Eugene Robinson writes: “[Texas Gov. Rick] Perry was supposed to be the ‘Shane’-like Western hero who brought peace to the troubled valley that is the Republican presidential field. A month after he rode into town, however, increasingly frantic GOP insiders are begging New Jersey Gov. Chris Christie to saddle up and save the day.” Or, as a GOP operative dismayed by the prospect of Perry as the nominee put it, “What hurts most is the way they fumble each and every response. Obama’s operation would filet these guys.”

And that, to a large extent, explains why Mitt Romney is not only still standing, but strengthening his position. He’s polished enough (too much so, his critics say), prepared enough, organized enough and scandal-free enough to beat the ailing incumbent president. In poll after poll you now see that Romney does better than Perry does against President Obama. The GOP can tolerate a lot in a nominee (even moderation on immigration, even RomneyCare) if he can beat Obama. Rep. Michele Bachmann (R-Minn.) is fond of saying that the GOP shouldn’t “settle.” But voters settle all the time; it’s losing that they can’t tolerate.

An example of Romney’s staying power is illustrated by a fundraising event hosted by the Republican Jewish Leadership group in New York last evening. I’m told by an attendee that there were about 200 in attendance. Romney spoke to both the host committee (more than 35 people who pledged to raise $10,000 each) and the larger gathering about the economy and Israel. He said both are on a tightrope and that we are in very serious times. He also talked about Obama being in over his head. The attendee explained that Romney’s “main theme on Israel is you stand strong with your ally who shares your values. Always stand together in public, disagreements private, or the bad actors will seize on the split. And then rather fluently walks you through the problems of the region (with no notes).”

In short, he is reassuring and stable. He sounds and looks like a potential president. He lowers the risk factor.

So while he’s hardly the heartthrob of the right and many sure would like to have another choice (more ideological than Romney, less likely to blunder than Perry), voters know they may not get such a contender. If there are no more competitors or the one they get isn’t much more conservative than Romney or much more polished than Perry, would they rally around Romney?

A GOP communications guru e-mailed me last night: “There’s something to be said for experience running — and losing — a national campaign, and Romney has that in spades.”

There is a way, of course, for Romney to boost his odds and deter a Christie run. Rep. Paul Ryan (R-Wis.) is speaking at the Hoover Institute in what is billed as a major speech on health care. It will be bold and serious. Romney should follow that lead — if not to the letter, then in substance. Announce his own plans (candidly embracing Ryan’s ideas) on Medicare, Medicaid, debt reduction, Social Security and restoring our military. That might preempt a late entrant and show conservatives Romney has more gumption than he’s given credit for. Or he could just cross his fingers that Christie won’t enter and that Perry will crumble.