Rick Santorum's three smashing victories Tuesday have turned the Republican presidential race upside down, again.
It has suddenly become a three-way contest with Santorum, Mitt Romney, and Newt Gingrich demonstrating regional popularity but lacking strong national appeal.
Santorum, a former senator from Pennsylvania, scored unexpectedly big wins in Missouri's non-binding primary and both the Minnesota and Colorado caucuses. His successes will insure that nationally, GOP voters will give him another look as a potential nominee and that the media will now scrutinize him as never before.
The losses for Romney, who was beginning to be considered as the front-runner, provided another sign that he still has serious vulnerabilities with his party's conservative base. GOP voters on the right remain unwilling to give him their full support and consider him unreliable as their standard-bearer.
Santorum won 40 percent to Romney's 35 percent in Colorado, with the other candidates far behind. Santorum won 55 percent to Romney's 25 in Missouri. He won 45 percent to Rep. Ron Paul's 27 percent in Minnesota, where Romney had 17 and Gingrich 11.
Santorum benefited from the battle that Romney and Gingrich have been waging against each other for weeks. Each of them has seen his negative ratings from voters soar, while Santorum has largely escaped scathing criticism and has maintained a mostly genial, hard-working presence.
In his victory speech in Missouri, Santorum said he is the most reliable conservative in the race and would offer the sharpest contrast to President Obama in the fall campaign.
"I stand here to be the conservative alternative to Barack Obama," Santorum said. Referring to Romney, he said the race is not based on big contributions and political organization, but conservative ideas.
The upshot: Santorum has won four contests in the Midwest and Rocky Mountain states--Iowa, Missouri, Minnesota and Colorado.
Romney, the former governor of Massachusetts, has won three contests in the East and West--New Hampshire, Florida, and Nevada.
Former House Speaker Newt Gingrich is emerging as a Southern candidate with a win in South Carolina and strong potential in other southern states.
The Associated Press estimated that Romney now has 107 nominating delegates, Santorum 45, Gingrich 32, and Paul 9. It will take 1,144 to win a majority.
Next up: the Maine caucuses, which conclude on Feb. 11. After that, there are primaries in Arizona and Michigan on Feb. 28. Washington holds its contest March 3, and 10 states, including Ohio, Georgia and Oklahoma hold primaries on "Super Tuesday," March 6.