Rick Santorum's slippery surge against Mitt Romney

Former Pennsylvania Senator Rick Santorum is on the rise. A CNN/Time/ORC International Poll saw Santorum's support triple since the beginning of December. The poll surveyed likely caucus participants in Iowa and likely primary voters in New Hampshire between December 21 and 27.

Former Massachusetts Governor Mitt Romney's support was at 25 percent. Rep. Ron Paul of Texas garnered 22 percent. Former Speaker of the House Newt Gingrich plummeted from a previous high of 33 percent down to a modest 14 percent of support.

Santorum, a former senator from Pennsylvania, emerged from the invisibility of 5 percent support to 16 percent — slapping him in third place as the Iowa caucus horserace turns the corner toward the finish line on Tuesday.

Of course this poll was five days ago. But as undecided voters shift their allegiances from one "not-Romney" to another "not-Romney" (an acceptable candidate other than Romney), the spoils may go to whoever peaks at the right time.

And with Iowa's caucus kickoff on Tuesday, a newer poll shows Santorum may be peaking at the best possible time.

Making up their minds

"Nearly half of Iowa respondents say they are undecided or could change their minds," CNN Polling Director Keating Holland told CNN.

One group that seems to be making up their minds are evangelicals. "Most of Santorum's gains have come among likely caucus participants who are born-again or evangelical," Holland told CNN, "and he now tops the list among that crucial voting bloc, with support from 22 percent of born-agains compared to 18 percent for Paul, 16 percent for Romney, and 14 percent for Gingrich."

Reuters sees the Christian conservative vote splitting between Santorum, Gingrich, Rick Perry and Michele Bachmann. The New York Times, however, said Santorum has to appeal to conservatives who are mostly concerned with the economy and national security — and he has to prove he can beat President Obama.

The Des Moines Register's final pre-Iowa caucus poll, conducted Dec. 27-30, may be more revealing, however. The who-voters-like-most breakdown is similar to the CNN poll:

24 percent Mitt Romney

22 percent Ron Paul

15 percent Rick Santorum

12 percent Newt Gingrich

11 percent Rick Perry

7 percent Michele Bachmann

2 percent Jon Huntsman

But the less-reported poll numbers are the who-voters-like-least:

23 percent Newt Gingrich

21 percent Ron Paul

14 percent Michele Bachmann

12 percent Mitt Romney

7 percent Jon Huntsman

6 percent Rick Perry

3 percent Rick Santorum

It's about time

Santorum's rise and likeability in Iowa may have to do with time.

Bloomberg noted Santorum has spent more time in Iowa than the other candidates and is getting results.

Reuters contrasted the amount of time Santorum's has spent in Iowa with Romney's. Romney spent millions in the state in 2008 but didn't really get rolling in Iowa this time around until last week.