(CNN) -- South Carolina voters sent a clear message Saturday to the GOP's Yankee frontrunner: not so fast.
Any hopes Mitt Romney had of bringing a quick end to the Republican presidential contest died in the Palmetto State. Newt Gingrich's easy win capped the worst week of the campaign so far for the former Massachusetts governor.
Instead of an unprecedented Iowa-New Hampshire-South Carolina Romney sweep, the first three states have now split between Rick Santorum, Romney, and Gingrich.
Gingrich's victory in the pivotal first Southern primary means the Republican contest now becomes a war of attrition, a fight for delegates that could drag on well into spring. The first man to get 1,143 delegates wins.
"We are now three contests into a long primary season," Romney told a crowd of supporters. "This is a hard fight because there is so much worth fighting for. We've still got a long way to go and a lot of work to do."
Gingrich's Saturday triumph reflected first and foremost South Carolina's status as one of the most conservative states in the country. Roughly two-thirds of primary voters described themselves as ideologically conservative, evangelical or born-again, and supportive of the tea party. The former speaker dominated Romney in all three categories.
Gingrich also received a huge boost from the two debates held over the past week. Voters took note as Romney stumbled over his tax returns while Gingrich used questions about his marital fidelity to rip the media -- always a favorite target of conservatives. About two-thirds of voters said the debates were an important factor in their decision, and they broke for Gingrich over Romney by about two to one.
Another apparent sign of the importance of debates: Gingrich dominated the field among voters who decided in the last few days -- a majority of the electorate. Romney and Gingrich were virtually tied among voters who decided earlier.
Concerns over Romney's Mormon faith also may have come into play in the strongly religious Palmetto State. Nearly 60% of voters said it matters somewhat or a great deal that a candidate shares their religious beliefs, and those voters broke for Gingrich over Romney by almost 25 points.
Two key matters of concern for Romney coming out of South Carolina: electability and acceptability. One of Romney's main strengths is the argument that he has the best chance of beating Barack Obama in November. In Iowa and New Hampshire, voters most concerned with electability backed Romney; in South Carolina they broke for Gingrich.
Is the conservative GOP prepared to rally behind Romney -- dismissed as a "Massachusetts moderate" by Gingrich -- if the former governor wins the nomination? Not yet. In deep red South Carolina, nearly 60% of primary voters said they'd only back Romney with reservations or wouldn't support him at all -- discouraging news for a candidate who will need an energized base to defeat Obama.
And yet, despite the bad news for Romney this weekend, he is still widely considered the frontrunner. Since 1980, no Republican has won the nomination without winning the South Carolina primary. But the former governor remains the man to beat because he retains overwhelming financial, institutional, and organizational advantages compared to his GOP rivals.
While Team Romney obviously would have loved a South Carolina win, they didn't start the race looking for a quick knockout. They studied Obama's long game against Hillary Clinton in 2008. They planned for a lengthy delegate contest. Neither Gingrich nor Santorum, in contrast, have serious ground games in place in the upcoming states. Both lack Romney's fundraising prowess.
Gingrich's supporters were able to reduce the financial disparity somewhat in South Carolina with the help of a one-time, multimillion dollar super PAC cash infusion from Las Vegas casino tycoon Sheldon Adelson. But their ability to continue minimizing the money gap in the long series of larger, more expensive states to come is unclear at best.
Florida's January 31 primary is next on the calendar. Romney has been on the airwaves across the Sunshine State since almost the beginning of the month, and reportedly has a major early voting effort underway. Gingrich is banking on momentum from South Carolina and two more debates -- next Monday and Thursday -- to level the state's playing field.
The former speaker's backers are also hoping Santorum folds soon, thereby allowing more of the anti-Romney conservatives to coalesce around his candidacy. Ron Paul's army of enthusiastic backers isn't going away, but the libertarian Texan is hampered by a low, hard ceiling of support.
Florida's primary is followed by February caucuses in Nevada, Colorado, Minnesota, and Maine. Missouri has a primary on February 7, while Arizona and Michigan hold their primaries on February 28. Romney is expected to do well in the caucuses because of his organization, while Michigan has virtual home state status for the former governor. Arizona and Nevada have significant Mormon voting blocs.
Voters in another 10 states -- including Virginia, where Gingrich isn't on the ballot -- weigh in on Super Tuesday, March 6. The last states don't vote until June.
Romney can go the distance. The question now is whether South Carolina helped give Gingrich enough fuel to do the same.