There are essentially three ways in which the outcome of a caucus or primary helps us to understand who will eventually win the party nomination.
The first way is the most literal: delegates are awarded, potentially bringing a candidate closer to the finish line.
The delegate tally is important in a state like Florida, which has a large number of delegates that are awarded on a winner-take-all basis. It’s less important in a state like Maine, where Mitt Romney won the presidential preference poll on Saturday night.
There were only 21 delegates were at stake in Maine, and they were chosen through a separate vote at the caucuses, which will bear an inexact relationship to the presidential preference vote once the state goes through the process of regional and state conventions. If you project the delegates from the popular vote in Maine, Mr. Romney would finish with the same number of delegates (8) as Ron Paul, and 4 more than Rick Santorum. But the eventual results may differ by a delegate or two or upward or downward.
The second way in which a caucus or primary is important is in its informational content: we learn something about how voters in a certain part of the country have behaved, and that might help us to make inferences about how things will go in future states.
By this criterion, also, Maine probably didn’t tell us very much. Mr. Romney won the popular vote there by just 3 percentage points. But, as I wrote earlier today, Maine is not necessarily all that strong a state for Mr. Romney once you examine its demographics and attitudes more carefully, even though he won by a much larger margin in 2008. On a scale that runs from 0 for the worst Romney primary state (say, Arkansas or something else in the Deep South) to 10 for his best one (say, Utah), it might rate at about a 6. If Mr. Romney is winning this sort of state by 3 points, it basically tells us that the G.O.P. nomination process is pretty close, which we already knew.
The third way a primary or caucus is important is because of the way it can affect the news media narrative and engender momentum. It’s in this way that Mr. Romney got something more tangible out of the state.
Yes, Mr. Romney’s margin of victory — 196 votes — was not overwhelming. But the fact is that Mr. Romney can very much use some favorable news of any kind, given how poorly he did last Tuesday.
Consider the alternative: if Mr. Romney had lost the state by 196 votes, the narrative might have been that Mr. Romney’s campaign was falling apart. That might or might not have been fair to Mr. Romney, but I think it’s possible that’s how it would have been perceived. People like to see patterns in the data, and the pattern would have looked like a bad one for his campaign. It was a smart decision for Mr. Romney to pay a late visit to the state, without which he might have lost.