It has been no secret around the Marriott Hotel bar here in Des Moines.

The strategic goal of the campaign of Gov. Mitt Romney was to put as many other candidates between him and either Gov. Rick Perry or former speaker Newt Gingrich as possible. Michele Bachmann trailed the field, so she was no help, but former Sen. Rick Santorum and Rep. Ron Paul did their jobs.

The Romney theory: Ron Paul will never be the GOP nominee. The best he can do is exact some language in the platform and get a prime speaking slot at the Republican convention in Tampa, Fla., in August.

Santorum did so well here because he has essentially lived among the beans, corn, and sorghum for the past 10 months and it paid off.  That, of course, will not work in New Hampshire, six days away, nor in South Carolina, 10 days after that, nor in Florida a week following South Carolina.

The political reality is that none of the candidates who might win the nomination has the capacity to fully operate in more than one state at a time. They are essentially running a serial campaign. Romney is running a parallel campaign. In fact, his campaign announced a few hours before the caucuses began that it was buying advertising time in Florida. Florida? Hell, that’s four weeks away! Perry originally said he would skip New Hampshire to set up shop in South Carolina, but, after barely keeping out of single digits, announced he would return to Austin to “reassess” his prospects.

Gingrich has promised—threatened, really—to attack Romney in New Hampshire all day every day for the next week. Santorum has said he will participate in New Hampshire, but a third- or even fourth-place finish there would halt his momentum, so he might well wave to New Hampshire voters on his way in and out of town to participate in the two debates next weekend, but claim he wasn’t fully engaged.

It also serves Romney’s purposes to have Perry and Gingrich stay in the race through South Carolina. If it turns into a Gingrich-Santorum-Bachmann steel-cage death match, it will soak up all of the most conservative votes, leaving Romney in the driver’s seat heading to Florida.

Only Romney can operate in high gear in all four January states, and having a weakened field against him leads us to only one conclusion:  Romney won.