Washington ? An upbeat Rick Santorum barreled into Puerto Rico on Wednesday in pursuit of another campaign-bending victory in a Republican presidential race where suddenly no primary is too minor and no delegate is conceded. Mitt Romney put nearly $1 million into television advertising in Illinois, the next big-state showdown.

“If we keep winning races, eventually people are going to figure out that Gov. Romney is not going to be the nominee,” said Santorum, eager to build on Tuesday’s unexpected victories in Alabama and Mississippi.

Romney in turn dismissed Santorum as a “lightweight” as far as the economy is concerned.

He also rebutted suggestions that he can’t appeal to core conservatives. “You don’t win a million more votes than anyone else in this race by just appealing to high-income Americans,” he said on Fox News. “Some who are very conservative may not be in my camp, but they will be when I become the nominee, when I face Barack Obama.”

Romney travels to Puerto Rico on Friday, after two days in New York fundraising.

But in a reflection of the importance of next week’s Illinois primary, aides announced he would make a previously unscheduled campaign stop in the Chicago area en route to San Juan.

Newt Gingrich, despite losing twice in the South, a region he hoped to own in the race, showed no sign of abandoning his fading campaign.

That presumably suited Romney fine. But not so much Santorum, eager for a race in which he is the sole challenger on the right for Romney, the former Massachusetts governor.

Despite his twin defeats in the South, Romney remains the faraway leader in the delegate chase. Incomplete returns showed him actually adding one or two to his advantage because of overnight caucus victories in Hawaii and American Samoa.