By Josh Lederman

Mitt Romney redirected his campaign fire at Rick Santorum on Monday in a sign he sees the former senator as a threat to his front-runner status.
Santorum is poised to do well in two out of the three GOP nominating contests on Tuesday. He has a narrow lead in the latest Minnesota poll and a solid chance of winning Missouri where Newt Gingrich isnt on the ballot and where Santorum has been campaigning more vigorously than any of his rivals.
The contests in those two states along with Colorado arent binding as to delegates awarded but will still determine the momentum heading into the two-week lull before the next primaries take place at the end of February.
Romney has made Gingrich the focus of his ire in the three weeks since Gingrich thrashed the former Massachusetts governor in South Carolina. But after solidly defeating the former Speaker in Florida and Nevada and watching his volatile campaign flounder Romney seems to no longer regard Gingrich as his most formidable foe.
Santorums key is tomorrow thats really his big day" said Republican strategist Ford OConnell who is unaligned in the race. If Santorum can win in Missouri and Minnesota thatll expose Romney as being weak in the Midwest and hurt him heading into Super Tuesday."
Romney campaigned in Colorado Monday a state he is expected to win. He canceled a previously scheduled trip to Minnesota citing travel difficulties which observers saw as a sign hes downplaying expectations in the state. The former Pennsylvania senator spent the morning in Minnesota and headed to Colorado in the afternoon.
Gingrich meanwhile is biding his time before Super Tuesday the March 6 round of primary contests that includes Southern states that are favorable to the former Speaker including Tennessee Oklahoma and his home state of Georgia.
But for Gingrich March 6 could come too late if Santorum racks up wins in the interim and converts those wins into a surge in the polls he could edge out Gingrich as the conservative alternative to Romney.
Hoping to blunt the possibility of a swell of support for Santorum Romney unleashed his most concentrated and severe attacks on Santorum since the days after the two fought to a near draw in Iowas Jan. 3 caucuses.
Romneys campaign blasted out a copy of Santorums 2008 endorsement of Romney hoping to make the former senators recent criticisms of Romney appear hypocritical.
Governor Romney has a deep understanding of the important issues confronting our country today and he is the clear conservative candidate that can go into the general election with a united Republican party" Santorum wrote four years ago.
Romney also dispatched one of his top surrogates former Minnesota Gov. Tim Pawlenty (R) to blast Santorum for saying he was proud of earmarks he had secured for Pennsylvania as its senator.
He clearly has been part of the big spending establishment in Congress and in the influence-peddling industry that surrounds Congress" Pawlenty said in a conference call with reporters. He has been a champion of earmarks and to hold himself out now as somebody who is an unquestionable conservative in these matters just is not supported by the facts."
Santorum not only shot back but used the escalating attacks to argue that Romney is trembling in his boots and letting loose an attack machine" in response to a Santorum surge.
Santorum spokesman Hogan Gidley accused Romney of rehashing a tired line of attack and relying on his financial advantage to distract voters from a record hes confident enough to defend.
I do think its smart for Romney to try to head off Santorum at the pass because he doesnt want to be caught in a position where Santorum suddenly catches fire and becomes like Newt and every other candidate in the race who has had some sort of bubble" said Kyle Kondik a political analyst at the University of Virginias Center for Politics.
Romneys disciplined and highly organized campaign is also likely aware that the dynamics on Tuesday will be different than in any previous contest. Its the first day of the primary process where there are multiple contests being held and the caucus format in Minnesota and Colorado favor very conservative candidates such as Santorum and candidates whose base is highly mobilized such as Texas Rep. Ron Paul.
And without Gingrich on the ballot in Missouri Romneys divide-and-conquer approach to his opposition has one fewer foil.
The conventional wisdom is Gingrich is going to be the chief alternative to Romney. That conventional wisdom could change tomorrow" said a GOP consultant who asked not to be identified in order to speak candidly.
When polls and caucuses wrap up on Tuesday the candidates will get a two-week reprieve until Michigan and Arizona vote on Feb. 28. Romney is currently positioned to sweep both of those states.
But as the erratic Republican primary has continually shown two weeks is more than enough time to swing the race in anyones favor.
Cameron Joseph contributed to this report.