Super Romney-Santorum showdown is here

WASHINGTON -- On the eve of their Super Tuesday showdown, Mitt Romney and Rick Santorum strained for an edge in Ohio yesterday and braced for the 10 primaries and caucuses likely to redefine the race for the Republican presidential nomination.

Newt Gingrich, though winless for more than a month, campaigned in Tennessee and issued a stream of signals that he intended to stay in the race.

In a race marked by unpredictability, Romney's superior organization and the support of an especially deep-pocketed super PAC allowed him to compete all across the Super Tuesday landscape. He can potentially pick up more than half of the 419 delegates at stake.

Santorum cast the race in biblical terms, his David vs. Romney's Goliath. Even that "is probably a little bit of an understatement," he added.

Primaries in Ohio, Georgia, Massachusetts, Vermont, Virginia, Oklahoma and Tennessee plus caucuses in Idaho, North Dakota and Alaska make today the busiest day of the primary season.

Unlike previous Republican campaigns, when a primary winner would typically win all of a state's delegates, allocations this year generally reflect the split in the popular vote. As a result, several candidates may be able to claim success, even in states they don't win outright.

Romney, a former Massachusetts governor and businessman, kept his focus on the economy in a final sprint across Ohio, which has drawn the most attention and television advertising. Pre-primary polls show him with momentum in a close race with Santorum, a former senator from Pennsylvania.

"Other people in this race have debated about the economy, they've read about the economy, they've talked about it in subcommittee hearings," Romney said. "But I've actually been in it. I've worked in business, and I understand what it takes to get a business successful and to thrive."

Santorum, who narrowly lost Michigan to Romney last week, said that no matter how much his rival spends, "conservatives will not trust him, will not rally around him this primary season. . . . We will be the nominee."

He said he looked forward to the day when Gingrich drops out and clears the way for him to challenge Romney, one-on-one.

Gingrich, the former speaker of the House, was having none of it.

Seemingly confident of a primary victory in Georgia, where he launched his political career more than three decades ago, he unveiled a new television commercial in Tennessee, promising to reduce the rising cost of gasoline. Eager to demonstrate his staying power, he said the commercial would soon begin running in Alabama and Mississippi, which hold primaries next week.

Texas Rep. Ron Paul, campaigned in Idaho after a weekend visit to Alaska, where he hopes to claim his first victory.