For the former US senator from Pennsylvania, it's confirmation that his persistent efforts to meet Iowans face to face are paying off. Already, other polls had shown him rising to 10 percent support in the state.
The new poll shows Mr. Santorum at 16 percent, just ahead of a sagging Newt Gingrich but behind Mitt Romney (25 percent) and Ron Paul (22 percent). The CNN/Time/ORC survey was conducted between Dec. 21 and Dec. 27.
The upward arc for Santorum also symbolizes something broader – the volatilty of the Iowa race and the hopes of other underdog candidates to make last-minute surges that could revive their campaign hopes.
The Iowa caucuses are a volatile affair spanning precincts around the state, with results affected by hard-to-predict turnout and last-minute appeals by the candidates.
Along with Santorum, Texas Gov. Rick Perry and Rep. Michele Bachmann of Minnesota face what many analysts see as make-or-break moments in the Hawkeye State. A surprisingly strong showing could propel one of them forward to compete in the next string of primaries.
But a weak showing could finish their campaigns. And they are campaigning like they know it.
Ms. Bachmann has been on a bus tour covering all 99 counties in the state. Governor Perry's bus is stopping at many of the same places, while his better-funded campaign keeps rolling out TV ads.
Each of them draws respect from Christian conservatives in the state, and Santorum has recently won some key endorsement from that camp. Bachmann and Santorum, in particular, has each sought to cast him or herself as the lone "consistent conservative" in the field.
This touted strength is also perceived by some voters as their weakness: The CNN poll found them bringing up the rear in perceived "electability" when matched against President Obama in the general election.
In a race that has seen almost every candidate shine as "flavor of the month," Santorum has not yet enjoyed a period of ascendency. Bachmann and Perry, by contrast, are struggling to recover from slumps after earlier rises.
Each of the candidates in Iowa gained ground with GOP voters in the recent poll except for Gingrich, who has faded quickly under a barrage of attack ads.
Santorum is the one who shows the biggest recent momentum, however. Where none of the other candidates have gained more than 5 percentage points over the past month, Santorum shot to 16 percent support after garnering just 5 percent in the poll conducted from Nov. 29 through Dec. 6.
He doesn't have big money for ads, but has rolled out radio spots that proclaim his conservative credentials, citing legislative successes on welfare reform, ending partial-birth abortion, and vigilance against the threat of a nuclear-armed Iran.
Bachmann also can't afford a huge ad blitz, and is focusing on her 99-county tour.
Perry is better funded. One of his new ads is called “Part-Time Congress,” a modest proposal to downsize the role of a legislative branch that has run up big deficits. "Cut their pay in half, cut their time in Washington in half, cut their staff in half," Perry says in the ad.
It's a jab, in part, at Bachmann, Santorum, Paul, and Gingrich (all of whom served in Congress and are pictured in the ad). If the CNN poll is right, though, Perry is behind Santorum in the race to be a surprise gainer from the Iowa caucus.