ST. LOUIS • Rick Santorum's bid for the White House was poised for a welcome boost on Tuesday, with the former U.S. Senator from Pennsylvania performing strongly among Republican primary voters in three states, even if his apparent win in Missouri was mostly symbolic.

Santorum, who is leveraging his appeal with social conservatives to make the case he is the leading alternative to GOP frontrunner Mitt Romney, is on track for the best night of the campaign since last month's Iowa caucuses.

Early returns showed Santorum leading in the Minnesota and Colorado caucuses.

Santorum also appeared to be the top vote getter in Missouri's "beauty contest" vote, which, because of an awkward attempt to comply with party bylaws, won't count towards awarding convention delegates.

Incomplete results showed Santorum leading Romney by a wide margin in Missouri.

Santorum invested more time and energy in the Show-Me State than any of his primary rivals, seizing on a rare, if unconventional opportunity, to go head-to-head with Romney.

Former U.S. House Speaker Newt Gingrich is also hoping to keep pace with Romney but, for reasons that remain ambiguous, did not sign-up for the Missouri ballot.

Santorum was the only candidate to do any meaningful campaigning in Missouri, appearing in St. Charles County and across the state last week. Santorum also apparently targeted likely voters with automated calls, a sign that he was treating the race as serious as a traditional contest, even with its lack of official import.

On Tuesday evening, Santorum returned to St. Charles, where a modest crowd is waiting to hear from him.