Rick Santorum got a rough result in the Washington caucuses on Saturday, finishing third in a state he had seemed to have a reasonable shot of winning. Now, Mr. Santorum’s slump is carrying over into the polls in crucial Super Tuesday states.

In Ohio, Mitt Romney has been the beneficiary of this. Although some polls still show Mr. Santorum with a lead, Mr. Romney was ahead in the majority of surveys that were conducted over the weekend and seems to have favorable momentum. Our forecast model there now shows Mr. Romney ahead by 2.5 percentage points there, and makes him a 2-to-1 favorite to win the state.

Mr. Santorum is also creating opportunities for his opponents in the two other Super Tuesday states that have been heavily polled, Tennessee and Georgia. Tennessee, where our forecast had given Mr. Santorum a 7-point lead over Mr. Romney and an 18-point lead over Mr. Gingrich based on polls conducted through Friday, now looks more like a three-way race. Mr. Romney has closed to within a point or two of Mr. Santorum and Mr. Gingrich is just 6 points behind.

In Georgia, Mr. Santorum has fallen below the 20 percent threshold that would allow him to be eligible to win statewide delegates, instead projecting to 19 percent of the vote. Mr. Gingrich has been the main beneficiary. Although he had always been favored in his home state, his forecast has climbed to 45 percent, from 40 percent, over the past three days, a figure that might allow him to win the majority in a number of Congressional Districts there and a larger number of delegates.

Between the three states, Mr. Santorum has lost an average of 3 points in his forecasts over the last three days — and this comes on top of some damage he had already endured after his losses in Arizona and Michigan.

At some points in the nomination contest, candidates who were penalized in the polls after enduring big losses rebounded fairly quickly. When Mr. Santorum held on to a lead in polls of Ohio conducted late last week, I saw some reason to be optimistic about his chances there.

But Mr. Santorum’s campaign — unlike Mr. Romney’s and to a lesser extent Mr. Gingrich’s — has lacked the muscle to turn the narrative around after some rough patches. This would have been a good week for Mr. Santorum to roll out endorsements, or to focus a line of attack upon Mr. Romney, but little of that has been apparent.

Instead, the past week has been relatively light for horse-race coverage, with much of the political world instead focused on the Rush Limbaugh controversy. With no debates — and Mr. Santorum’s loss in Washington representing the major story — there has been nothing to stop his downward trajectory.

It’s possible, in fact, that Mr. Santorum’s victories Tuesday night could be limited solely to Oklahoma. Caucus states like North Dakota and perhaps Alaska had once looked more promising to him, but he has not been able to replicate his strong showings in Colorado and Minnesota in more recent caucuses. Without a burst of voter enthusiasm in those states, his relatively weak organization could harm him, possibly leaving Ron Paul as the major rival to Mr. Romney in them instead.

We will, of course, have to see how everything plays out. At some points, Mr. Santorum has tended to overperform his polls on Election Day, and doing so by even a couple of points in Ohio and Tennessee would allow him to salvage an otherwise poor night.

Still, things like Mr. Santorum’s declining numbers in Georgia, and his failure to file a full slate of delegates in Ohio, will pose challenges for him in the delegate math. Even with three or four narrow wins, Mr. Santorum could still easily yield 100 delegates to Mr. Romney. And if his negative momentum manifests itself at the ballot booth Tuesday, he could also finish with fewer delegates than Mr. Gingrich on the evening, even though Mr. Gingrich is not expected to be competitive outside of the South.