Rick Santorum’s breakout moment

>>> good evening. as one veteran of republican politics put it last night, the romney bandwagon just rolled into a ditch. to view last night's results as just a story about a stumble by the gop front-runner would be a mistake. it was an extraordinary night for rick santorum , though he doesn't come out of it with any more delegates yet. he pulled off a hat trick winning primaries and caucuses in three states, stitching together a victory map that includes iowa and exceeds the number of romney wins. at least for now, this race has changed yet again after what's being called today rick santorum 's breakout moment. we begin on the trail tonight with nbc's kelly o'donnell in allen, texas . good evening.

>> reporter: good evening, brian. rick santorum will be dropping by this meeting of tea party activists in texas tonight. few could have imagined he would be riding so high sweeping colorado, minnesota, missouri, after that that iowa win you mentioned and santorum with four victories to romney 's three. making another shake-up in this wild primary season. a victorious rick santorum began his days surrounded by the prayers of a texas congregation.

>> we pray you direct rick's steps as he campaigns for president.

>> reporter: santorum is in his comfort zone picking on social issues and talking about faith. success is the new territory.

>> one of the great gifts i had in my political career is no one ever thinks i could ever win anything.

>> reporter: short on the typical necessities, money and campaign organization, santorum rebuffed presumptions that mitt romney is the republican's inevitable nominee.

>> i don't stand here to claim to be the conservative alternative to mitt romney . i stand here to be the conservative alternative to barack obama .

>> reporter: santorum 's blue collar roots appear to prompt a new personal story from the uber wealthy mitt romney , who referred to his auto executive father's early days as a carpenter's apprentice.

>> he could take a handful of nails, stick them in his mouth and spit them out pointing and forward.

>> reporter: santorum 's moment had the benefit of good political timing. santorum , who is catholic, has been hammering the white house over the rule that requires some religious-based employers to provide coverage for birth control, despite fierce objections from the catholic church .

>> this administration, as you can tell from my reaction, has been hostile to people of faith, particularly christians and specifically catholics.

>> reporter: while many republicans, including mitt romney , demand the rule be reversed, today the white house hit romney over similar requirements in his state's health insurance .

>> former governor of massachusetts is an odd messenger on this.

>> mr. carney needs to check his history.

>> reporter: landing in atlanta, romney fought back.

>> in the working on our health care plan, worked very hard to get the legislature to remove all of the mandated coverages, including contraceptives.

>> reporter: now, with romney taking fire from all sides, he has a new attack against santorum tonight, pairing him with gingrich calling them republicans who act like democrats. going after their records on earmarks and spending while in congress. if you're wondering about gingrich, he's campaigning in ohio and his dismal performance didn't get much attention, overshadowed by santorum 's success.

>> kelly o'donnell in allen, texas .