DES MOINES, Iowa -- Rick Santorum zoomed out of virtual obscurity in Iowa in a matter of weeks and surprised many observers by virtually tying Mitt Romney in the Iowa caucuses Tuesday. But Santorum has more work to do if he is to convince the broader Republican Party that he is better equipped to challenge President Barack Obama than Mitt Romney.
The next test for Santorum lies in New Hampshire, where Republicans will vote in their primary in just one week, on Jan. 10.
It is a stunningly short amount of time for the former Pennsylvania senator to make up ground in the Granite State on former Massachusetts Gov. Romney, who eked out a narrow victory in Iowa. The latest polls from New Hampshire before the Iowa result showed Santorum at an average of 4 percent to Romney's 41 percent.
And before the final results from the Iowa caucuses had even finished coming in, the Romney campaign rolled out the welcome mat for Santorum, announcing that Sen. John McCain (R-Ariz.) -- a favorite son of New Hampshire voters -- will endorse Romney on Wednesday at a rally in New Hampshire.
Nonetheless, Santorum will get a huge boost from his Iowa finish, both in support and fundraising. And New Hampshire is known for its penchant for giving long-shot underdogs a shot.
"Game on," Santorum said as the final caucus results trickled in and continued to see-saw the lead back and forth between Santorum and Romney.
Santorum could also pick up a few points if Rep. Michele Bachmann (R-Minn.) drops out. It's not yet clear if she will do so in the next week, though several campaign aides said they were not sure if she would continue or that they had already told -- or would tell -- her not to continue. Iowa conservative leaders also called on her Tuesday night to end her campaign.
Yet former House Speaker Newt Gingrich (R-Ga.) -- who is polling at around 12 percent in New Hampshire -- signaled he will take the fight to Romney in the state, perhaps complicating Santorum's attempt to consolidate support from anti-Romney voters.
"We are not going to go out and run nasty ads," a feisty Gingrich said in his speech after the results came in. "But I do reserve the right to tell the truth."
"There will be a great debate in the Republican Party before we are prepared to have a great debate with Barack Obama," he said.
Michael Dennehy, a New Hampshire GOP consultant, said Gingrich will make it harder for Santorum to pick up ground on Romney.
"He needs to figure out a way to coalesce the entire conservative vote, which is a monumental challenge given that Gingrich is still getting 10 [plus] percent and he has the Union Leader," Dennehy said, referencing the endorsement of Gingrich by the influential New Hampshire newspaper.
Looking ahead to South Carolina's Jan. 21 primary, the path did potentially clear for a Romney alternative such as Santorum, as Texas Gov. Rick Perry –- who received just 10 percent of votes in Iowa -- signaled he was likely taking himself out of the race.
"I've decided to return to Texas," Perry said, continuing that he will "determine whether there is a path forward for myself in this race."
The Romney campaign is ready for a long and sustained battle if the primary heads that way.
But the next few days leading up to next Tuesday's vote in New Hampshire will largely serve to demonstrate how much momentum Santorum can gather, in hopes of putting himself on even footing with Romney in the eyes of voters. It will be a test not only of Santorum's viability but also of how strong the anti-Romney sentiment is in the Republican Party.
When Romney emerged before the crowd minutes before midnight, he congratulated Santorum and projected confidence.
"This has been a great victory for him and his effort," Romney said of Santorum. "We also feel it's been a great victory for us here."
"Thank you Iowa for the great sendoff you're giving to us," he said.
But Romney's finish at the top was still a disappointment, since the campaign had clearly tasted victory here and had spent the last few days predicting a win.
"We're going to win this thing," Romney said on Monday, in a momentary slip that revealed the confidence within his campaign. The Romney campaign was seeing overnight call numbers leading up to Tuesday's caucuses hitting numbers a few points higher than what they thought they needed to win.
So Romney let expectations grow for him to win Iowa after he had worked all year to minimize the Hawkeye State, given the way it embarrassed him four years ago. Romney -- who came to Iowa for over 100 days in 2008 -- visited the state only twice prior to October. He hired only five staff in the state, a far cry from the 52 staff that got on Romney's Iowa payroll in 2008.
But as conservative alternatives -- Perry and then former Godfathers Pizza CEO Herman Cain and then Gingrich -- rose and fell through the Fall, Romney and his inner circle decided in early December to try to steal an Iowa win. Romney ended up coming to the state six times in November and December, and then spent a full week here in the run up to Tuesday night's caucuses.
Romney had never spent more than two nights in the state before the past week. In all, the final week of campaigning boosted his total time spent in Iowa this year to 18 days.
Romney did much better than his nine-point loss to former Arkansas Gov. Mike Huckabee in 2008. But it turned out that Iowa was still a tease. Romney has a long way to go yet to clinch the nomination, and will have to move quickly to forestall an explosion of support within the GOP for Santorum.
"On to New Hampshire," Romney said. "We've got some work ahead."
This story has been updated to reflect the final results of the Iowa caucus, narrowly won by Mitt Romney.