Tim Pawlenty announced today his departure from the presidential race. The decision is understandable. In the Ames Straw Poll, Pawlenty went all in. He spent a fortune (maybe a million dollars). He received 2,293 votes, less than half the votes Rep. Michele Bachmann (R-Minn.) did. He also got less than half the votes Rep. Ron Paul (R-Tex.) did. He threw punch after punch at Bachmann, none landed. He’s in deep trouble. As an aside, I wonder what all those people are thinking who in 2008 said, “If only John McCain chose Pawlenty as VP!”

His record was solid; his persona and retail politicial skills were insufficient. His campaign, as those caught in a death spiral often are, became increasingly dysfunctional. In failing to aggressively and effectively pursue Romney and then Bachmann he demonstrated his own lack of personal authority. His departure leaves Mitt Romney with no real challenger for moderate and centrist Republicans.

But as Pawlenty exits, a new figure may be emerging. Rick Santorum only raised $582,348 in the second quarter. As of late July, records obtained by Right Turn indicate he spent $19,000 on media buys in Iowa. Santorum didn’t do that much worse than Pawlenty. He garnered 1,657 votes. He now has new life.

Penny Nance, head of Concerned Women for America, wasn’t surprised by Bachmann’s Ames win, but she had praise for Santorum. “I am very happy for Rick Santorum. He is a good friend and a principled leader.” There are other social conservatives who may feel the same way, and now not worry that a donation or volunteer effort would be “wasted” on Santorum.

Santorum remains the longest of long shots to win Iowa (let alone the nomination), but a race without Pawlenty and with a well-funded Santorum would change the complexion of the campaign. As we saw in the Iowa debate, Santorum has no compunction about attacking Bachmann for her inflexibility in Congress. He’s every bit as conservative as she and also has been a lawmaker. He, therefore, has more credibility in challenging her on her “no” votes (on the budget, on the debt-ceiling, etc.).

In his confrontation with Rep. Ron Paul (R- Tex.), Santorum also showed his flair in knocking down 10th Amendment-philes. Santorum said on Thursday night: “We have Ron Paul saying, what the states, whatever they want to do on the 10th Amendment is fine. If they want to pass polygamy, fine, sterilization, fine. No, our country is based on moral laws.” (Well aside from “moral laws,” there are Constitutional rights on which the states cannot infringe and there are plenty of areas in which the federal government does exercise authority.) Santorum may give Texas Gov. Rick Perry a run for his money, should Perry intend to press his 10th Amendment arguments.

Santorum is also extremely tough on foreign policy issues, and with the benefit of Senate experience, has some detailed knowledge at his finger tips. That, too, can pose a challenge to the other candidates less well-versed and less tough on national security.

None of this is to say that Santorum is yet a top-tier candidate. However, he certainly is a more dangerous competitior than Pawlenty. Pawlenty’s departure and Santorum’s ascension won’t be good news for the rest of the field. But it could make for more interesting debates.