Conventional wisdom holds that today’s Republican primary in Florida will narrow the race to two candidates – John McCain and Mitt Romney. Further wisdom from the convention holds that next Tuesday’s multiple primaries will determine which of the two men will receive the nomination.

I won’t disagree with that wisdom, whether or not it proves to be truly wise. Bloggers on the progressive end of the spectrum are cheering for Mr. Romney, on the theory that the treacle-oozing former Massachusetts governor will be easier for the Democratic candidate to beat in November.

Mr. McCain, with his reputation (deserved or not) for straight talk, his entourage of adoring reporters and his ability to appeal to independent voters is thought to be a threat to the Democrats, especially if he matches up against Hillary Clinton. Her selling points – an experienced hand, ready to be commander-in-chief on day one – better describe Mr. McCain than Ms. Clinton.

But here’s the rub – Mr. McCain’s candidacy is only alive today because of the decrease in violence in Iraq in 2007. His campaign nosedived last spring when he – courageously – tied his political future to the success of the surge in US combat troops. When it looked like the surge worked, Mr. McCain’s candidacy came back from the dead.

Now the top issue on voters’ minds is the economy. From the looks of the recession we’ve entered, this will be the issue that will dominate the general election and John McCain, by his own admission, doesn’t know as much about economics as he does about military or foreign policy.

His most notable foray into domestic economics came early in his Senate career when he helped create the savings-and-loan debacle by getting federal regulators to back off their oversight of unethical McCain crony (and political contributor) Charles Keating. To his credit, Mr McCain admitted he’d been wrong and acted like an idiot, but idiocy is a poor qualification for the presidency.

So, if the economy is the number one issue, then perhaps Mr. McCain would be a better punching bag for the Democrats than Mr. Romney, whose background is in corporate management.

The only way to get the subject changed from economics to Mr. McCain’s strong military or foreign policy suits is for something to happen in Iraq. It’s entirely possible – even probable – that big things will happen in Iraq between now and November. What’s not probable – perhaps not even possible – is that a good big thing will happen in Iraq.

As the New Yorker’s Jon Lee Anderson reported last November Moqtada al-Sadr’s Madhi Army has been standing down since August and is supposedly going back into action in March, just about the time both American political parties will have settled on candidates.

If the economy remains sour – as is likely – and continues to dominate the electoral debate, that’s bad news for John McCain. If the subject shifts back to Iraq, it will likely be due to an unhappy turn of events – also bad news for John McCain.

Any way you look at it, it’s a tough year to be a Republican.