(USA TODAY)DES MOINES, Iowa -- If either Paul Ryan or Hillary Rodham Clinton truly is on the fence about running for president of the United States, some pop-the-champagne poll numbers froma new Des Moines Register Iowa Pollmight encourage them.
But if Rick Santorum feels confident he could win Iowa again, the new poll could burst his bubble.
The Iowa Poll examined reactions in the leadoff presidential voting state to six "re-runs" - Ryan, Clinton, Santorum, Joe Biden, Mike Huckabee and Rick Perry, politicians who ran for the White House in 2008 or 2012 who are being talked about again for 2016.
One key finding: There's a 30-point difference between Iowa Democrats' attraction to another Clinton bid (88 percent) and another Biden bid (58 percent).
Among Iowa adults overall, half think it's "a good idea" that Clinton, the former first lady and former U.S. secretary of state, run again. That's the high-water mark among the six candidates tested.
"If I'm advising Secretary Clinton, my biggest advice is that these are great numbers, (but) never take Iowa for granted," said Democratic strategist Robert Shrum, who helped lead Democrats Dick Gephardt and John Kerry to victory in the Iowa caucuses in 1988 and 2004.
More independents (50 percent) want to see Clinton run again than favor the candidacy of any other politician tested.
Iowans' support for another Clinton presidential bid tracks closely with national support in a USA TODAY/Pew Research Center poll released last week. Fifty-one percent of Americans say they'd like her to run in 2016, including three of four Democrats. Forty-three percent want her to sit it out. The poll was conducted March 1-4.
When it comes to Biden, the thought of another presidential campaign makes most Iowans blanch. Only 33 percent of Iowa adults say it's a good idea, while 57 percent give the idea a thumbs down. The vice president gets a green light from a majority of Democrats (58 percent).
Women drive the gap between Clinton and Biden in the support each receives for running again. While 57 percent of Iowa women want to see Clinton try for the White House again, only about a third of women want another Biden race.
The poll of 703 Iowa adults was conducted Feb. 23-26 by Selzer & Co. of Des Moines. It has a margin of error of plus or minus 3.7 percentage points.
On the GOP side, Republicans clearly want Ryan in the mix again: 67 percent say it's a good idea for the 2012 vice presidential nominee to run for president this time.
"Paul Ryan is the consistently most popular Republican official in the country, no matter where you look," said Republican Brad Todd, a D.C.-based ad-maker.
Among Republicans, Ryan, a Wisconsin congressman, gets slightly more support for a second bid than does Mike Huckabee, winner of the 2008 Iowa caucuses, at 65 percent. Both get a lot more support for a retry than does Perry (50 percent) or Santorum (48 percent), the 2012 caucuses winner.
Shrum, who was a senior fellow at New York University and soon will start as Warschaw Professor of the Practice of Politics at the University of Southern California, thinks Ryan's high regard in Iowa "says you have Republican caucusgoers who are getting serious about winning. The person who's doing the best in this list is also the most plausibly presidential."
With the GOP caucus crowd's conservative tilt, first-timers like Kentucky Sen. Rand Paul or Texas Sen. Ted Cruz can walk in and do very well, Shrum said. "That's probably true unless you have Paul Ryan running."
Santorum, the guy Iowans got to know best in the 2012 caucuses and thrust into a last-second victory, has less than half of Republicans on board with the idea of another run.
"He clocks in two points lower than Rick Perry among Republicans who think it's a good idea that he runs? This is the last Iowa caucus winner?" said GOP strategist David Kochel, who was Santorum competitor Mitt Romney's Iowa strategist last presidential cycle. "It looks like Santorum is one and done in Iowa."
Shrum said: "What was appealing about him - the sweater vest and all that - looks very superficial now. They see someone they can't send to the White House."
Republican poll respondent Buffalo Bonker, a 43-year-old Des Moines artist, thinks it's a bad idea for Santorum to run again.
"I'm just opposed to the whole anti-gay-marriage campaign that he led," said Bonker, who caucused for Huckabee in 2008 and Ron Paul in 2012.
The poll numbers show Huckabee is still formidable in Iowa. The former Arkansas governor's star turn on Fox News has apparently had positive effects, GOP strategists said, reinforcing interest among his base inside the party.
Huckabee does better with independents (39 percent say they want to see him run again) than any of the candidates tested except Clinton.
Poll respondent Abid Wahid Butt, 59, an independent voter from West Des Moines, said: "I think Santorum is too far to the right and that's going to hurt him. Huckabee, I think he's conservative, but he's more toward the middle. I think he still has a good bit of support, and I think he has a better chance of increasing his support base than Santorum does, definitely."
Huckabee gets slightly more support for a second run among women (45 percent) than men (43 percent). The other GOP candidates get more support from men for another bid than from women.
Huckabee's support among women "is a huge selling point, especially for a social conservative," Kochel said. "Likeability is his biggest asset, clearly."
The numbers offer Perry, the retiring Texas governor, hope that he's making progress with rehab among GOPers in Iowa. Half of Republicans think it's a good idea for him to run again, as do 52 percent of Iowans who call themselves tea party supporters. Just a third of Iowans of all political leanings invite a rerun.
The poll was conducted just before Perry hit Iowa for another two-day visit with reporters and GOP activists.
"The good news is Republicans are willing to give him a second look and he's earned it, but among all voters for now, the damage to his image continues, due to the collapse of his last campaign amid bad debate performances and weak finishes in the first two contests," Kochel said. "Once the first impression is burned into the minds of voters, it can be difficult to erase."