Perhaps Mr. Santorum’s campaign perceives that Mr. Romney is close to the 50 percent threshold. If so, spending some time in Puerto Rico could prevent Mr. Romney from hitting that mark, perhaps limiting him to 9 or 10 delegates rather than 20.

It’s a “small ball” strategy, in other words — one focused on the delegate math. Mr. Santorum is seeking to spend his resources efficiently to limit Mr. Romney’s advantage in that department.

This kind of strategy, however, misses the forest for the trees. The problem with it is simple: it is almost certain to be a losing one…

Game-changing events are not easy to come by, of course. But Mr. Santorum’s campaign does not seem so interested in maximizing his chance at achieving one. His travel schedule is one such example: Mr. Santorum spent part of last week in Puerto Rico, and will be spending part of Sunday in Louisiana, rather than focusing on Illinois, a state where polls and demographics give Mr. Romney an edge but only a modest one.

A win in Illinois would do much more than anything that might happen in Puerto Rico or Louisiana to alter the momentum in the race. At a bare minimum, it would position Mr. Santorum better for Wisconsin, which votes on April 3 and has 42 delegates — twice as many as Puerto Rico — and awards them on a largely winner-take-all basis.