Not that you would know it by watching him on the campaign trail, where the perpetually optimistic candidate has been drawing standing-room-only crowds and promising his political fortunes will improve if he can make it to just one more state.
"The more that this campaign evolves, the better we are going to look to be the best candidate to defeat Barack Obama," the former Pennsylvania senator said Sunday as he toured the factory that produces the sweater vests he sells for fundraising. "I feel confident that we're going to do well here in Minnesota. We're going to do well in Missouri on Tuesday and I think we're also going to do well in Colorado. At least I hope to do well in Bemidji anyway."
A day earlier, he came in last place in Nevada. He didn't mention the latest setback when he attended church services Sunday, showing no sign the GOP contest was slipping through his fingers.
"I'm trying to walk the path that Christ has laid out for me. I'm just trying to discern his will," he said during services at Lake Eden's Grace Church. "I will leave it up to him as to how everything turns out."
Taking his ragtag campaign across the country, Santorum hopes to amass enough delegates to the Republican convention this summer to earn greater stature within the party even if he fails to achieve the GOP nomination.
It's been a month since Santorum narrowly won the Iowa caucuses and, while outright victory may be out of reach in the next states to vote, he's looking to make a statement here and in Colorado. In Missouri, Newt Gingrich is not on the ballot, giving Santorum a better chance to make an impression against frontrunner Mitt Romney.
Minnesota could be fertile territory for Santorum, with its small contingent of highly conservative caucus-goers. It borders Iowa, where Santorum was the declared winner in the campaign's lead-off caucuses a month ago. He is also looking at Colorado, where deeply conservative evangelicals have an unshakable foothold. Santorum has picked up the backing of prominent social conservative and Focus on the Family founder James Dobson, who joined him for campaign appearances in recent days.
To be sure, Santorum faces an uphill battle to win the party nod.
Santorum has little money and virtually no momentum. He's trailing badly in national polls. He's had trouble getting on ballots in Virginia and Indiana. And he has essentially no staff in upcoming states - much less anything resembling the national operations his rivals are running.
He no longer has a national campaign headquarters; technically, he calls a post office box in Pennsylvania his base camp. His inner circle is seldom in the same location. His campaign manager is a New Hampshire consultant. His deputy campaign manager is Iowa-based and was only recently named to that role in an official capacity. His senior political adviser runs a firm in South Carolina and calls it home.
Santorum's accommodations are sometimes determined by which supporter has an extra guest room, and his transportation sometimes is a volunteer's pickup truck. And when reporters have questions, they simply walk over to the senator and ask him instead of calling his spokespeople in Pennsylvania, Washington or South Carolina.
Yet, his team celebrates its off-the-cuff style. Some only just recently started getting paychecks, and some of the people who have day-to-day responsibility for his events aren't on the payroll yet.
"We are running this campaign on a shoestring," Santorum says. "But that is an insult to shoestrings."
He and his aides insist the nomination is still not out of reach.
They count themselves as students of how Barack Obama won the Democrats' nomination four years ago: don't look at the win/loss column and instead focus on the slow accumulation of convention delegates.
Under GOP rules that are new this year, anyone who gets a certain portion of the vote in each state qualifies for a delegate to the GOP convention in Tampa. So while Romney and Gingrich are assailing each other, Santorum and his aides argue, he gets the chance to introduce himself to more voters and pick up delegates here and there on the cheap.
"There is a chance that we could go to the convention," Santorum argued in Fallon, Nev., last week. "I don't think that's a bad thing. I think that would be a healthy thing. From my perspective, the longer this primary goes on, the better."
Santorum is banking on Gingrich collapsing under Romney's withering criticism, leaving Santorum in the coveted and fluid role of the leading conservative alternative to Romney.
For now at least, Santorum is attracting standing-room only crowds and hoping voters grow weary of the Romney-Gingrich rivalry.
"Every time you hear about this race, it's just Romney and Gingrich," said Cheryl Rawlings, a 59-year-old retiree from Hannibal, Mo., who met with Santorum at the Mark Twain Dinette on Friday. "Santorum isn't making the headlines, but look at the people outside here waiting to meet him. This is not a two-man race no matter what the media would like."