Republican presidential candidate Rick Santorum’s underdog path to the White House appears to run along the Mississippi River – and Missouri is among the next stops.

That’s the assessment of Dave Robertson, a political science professor at the University of Missouri-St. Louis, as he looks at the political landscape following the 10-state juggernaut of primaries and caucuses known as Super Tuesday.

Although Republican frontrunner Mitt Romney captured the most delegates and won six of the states, Robertson says that Santorum’s latest victories in three states – and his close runner-up finish in Ohio -- put the former Pennsylvania senator in a good position to win in Mississippi and Alabama.

Those two states are considered Santorum-friendly turf and would add to his early wins in Iowa, Minnesota and Tennessee – all along the river as well.

Then Santorum can turn to Missouri’s March 17 Republican caucuses (which actually will begin March 15 and run through March 24).

Santorum is planning to visit Missouri this Saturday, with campaign stops in Springfield, Mo. and Cape Girardeau. Rival Ron Paul is scheduled to appear Saturday in St. Charles and in Springfield.

Santorum and his allies hope to duplicate his huge statewide victory in Missouri’s Feb. 7 non-binding primary, in which he carried every county. Missouri is among the states where evangelicals and religious conservatives -- Santorum blocs -- are key forces within the GOP ranks.

Start of update: Former St. Charles County Executive Joe Ortwerth is among the religious conservatives backing Santorum. "I expect that his supporters will show up in very strong numbers at the caucuses to continue to provide major momentum to his presidential campaign," Ortwerth said. "Pro-life and pro-family Missourians continue to have a strong allegiance to Sen. Santorum because of his heartfelt convictions on issues of faith and family. Missourians admire Sen. Santorum's sincere commitment to the values of working-class families" End update.

Romney, however, continues to hold most of the big-name Republican endorsements in Missouri, including former Sens. Jim Talent and John Ashcroft, current state Auditor Tom Schweich and U.S. Sen. Roy Blunt.

Start of update: On Thursday, that list fattened to include former U.S. Sen. Christopher "Kit" Bond, R-Mo. End update.

That heft could help the former Massachusetts governor out-organize Santorum and grab Missouri's 52 presidential delegates.

Blunt chose his words carefully as he predicted Wednesday that the Republican presidential contest is far from over.

"This process is going to last for a while, and that makes Missouri and every state that has not yet selected their delegates more important than they might otherwise be,” Blunt said. “And, frankly, more important than most people thought a mid-March and then-April delegate selection process would be.”

Blunt is referring to Missouri’s tiered caucus system, which begins with a crowd of county and township meetings – most on March 17 – when people will pick representatives to attend the next round of congressional-district caucus meetings April 21 and the state convention in June.

Caucus setup may favor Romney

The April caucus meetings will determine which presidential candidate – or candidates – receive the majority of the state’s 52 delegates to the August presidential convention in Tampa, Fla.

As a result of the setup, a state party spokesman emphasized that the party would have no definite results to report after the March 17 caucuses. No votes will be taken, and the representatives chosen at those sessions (for the congressional district round) don’t have to declare their favored candidate.

In any case, Ken Warren, a political science professor at Saint Louis University, predicts that Romney's increasing inevitability as the GOP presidential nominee will likely shift more Missouri caucus-goers his way.

“To me, it’s pretty much over,” Warren said. “I know that next week’s going to look bad for Romney, but … the delegate count looks really bad for the rest of the field. As I see it, only Romney has a real chance.”

Warren compared Santorum’s present situation (what he termed “a gradual rejection of Santorum”) with that of 2008 Democratic presidential candidate Hillary Clinton late in the Democratic primaries, before rival Barack Obama finally secured the nomination.                .

“In 2008, I thought that after South Carolina it looked really bad for Hillary Clinton. And after a few more weeks of caucuses and primaries, it became clear that the only way she could win would be ‘Hillary math,’ ” Warren said.

“As I see it, that’s the situation now for Santorum. I don’t really see that Santorum stands much of a chance as we turn to ‘Romney kind of states’ after next week: New York, Connecticut and California.

“How does that affect Missouri. Well, it affects Missouri because I think the Republican delegation in Missouri is going to feel the same way,”  Warren said.

Battleground St. Louis County

St. Louis County provides the largest bloc of votes in any statewide election, and that may be true for caucus involvement as well.

St. Louis County will have 28 caucus sites on March 17 -- by far the most of any county in the state.  Each site will be in one of the county's 28 townships.

County Republican Party chairman Rich Magee said that he already has seen organizational activity by field staff or supporters for Romney and Paul.

Paul opened a state headquarters in Brentwood this week and is supposed to speak in St. Charles on Saturday at 3 p.m. at Lindenwood University.  Talent, the former U.S. senator, was the featured speaker at last Saturday night's St. Louis County GOP Lincoln Days dinner.

“I do see a concerted effort on Romney’s part,’’ Magee said.  He has yet to see any field staff for Santorum, but Magee added that he’s hearing and seeing a lot of interest from rank-and-file Republicans who are social conservatives.

For supporters of any candidate, Magee said, the strategy will be the same for the March 17 caucuses. “You want to flood each township caucus,’’ he said, to control the selection of representatives to the April round, when the delegates will actually be doled out.

In short, emulate the Mississippi River in the spring.