WASHINGTON (Reuters) - Rick Santorum and Marco Rubio are the top two choices among Republican voters as Mitt Romney's vice presidential running mate, according to a Reuters/Ipsos poll released on Thursday.
Eighteen percent of Republican registered voters picked former Pennsylvania Senator Santorum out of a list of 19 potential running mates for Romney, the party's presumptive presidential nominee in the November 6 general election.
Seventeen percent chose Rubio, a U.S. senator from Florida. Rubio was also the most popular pick among members of the Tea Party movement, a group that Romney wants to win over as he works to solidify his support among the party's conservatives after a divisive primary fight.
New Jersey Governor Chris Christie and former Florida Governor Jeb Bush were tied for third among Republicans, with 13-percent support, and 12 percent picked former Arkansas Governor Mike Huckabee.
None of the other potential vice presidential picks was higher than 6 percent, largely because they are unfamiliar to most voters, Ipsos pollster Chris Jackson said.
Congressman Paul Ryan , well known in Washington for his cost-cutting budget plan, w as one big name with scant support at just 4 percent. Despite campaigning with Romney in Wisconsin recently in what was seen as a try out for a possible vice presidential nomination, Ryan was familiar to only a third of the registered voters polled.
Almost a quarter of Tea Party members picked Rubio in the online poll, compared with 16-percent support among the group for Santorum, who ended his own presidential run last month.
But Rubio might not be the best choice of running mate if Romney wants to appeal to independent voters in the general election against President Barack Obama.
The 40-year-old Cuban-American senator was backed by only 4 percent of independents, behind other top Republican names mentioned in the vice presidential stakes.
There has been speculation he might help Romney win over Hispanics, with whom he trails Obama by a whopping 40 percentage points, but early polling has not borne that out.
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Romney was to meet former bitter rival Santorum in the Pittsburgh area on Friday to clear the air after a heated primary battle.
As he battled Romney - winning about a dozen states - the socially conservative Santorum leveled charges including saying Romney was "the worst Republican in the country" to face Obama.
Santorum is best known for his strong opposition to abortion and gay rights and his support could help Romney win over religious conservatives. He is familiar to voters because of his strong performance during the primary race, but is one of the most polarizing potential vice presidential picks.
Familiarity can cut both ways. Among all respondents, Santorum had the highest unfavorable ratings, at 23 percent.
"If he hadn't earned so much media coverage over the last couple of months, I don't think he'd have been here at all. He's viewed pretty unfavorably by a pretty big slice of the electorate, mostly Democrats and independents," Ipsos pollster Chris Jackson said.
Sixty-four percent of registered voters said they were familiar with the former candidate.
Bush, at 21 percent, was the only potential VP pick whose overall disapproval rating rivaled Santorum's. Though well known nationally, Bush is closely associated in many Americans' minds with his brother, whose approval ratings plunged before he left office in early 2009.
Santorum has been reluctant to endorse Romney and no endorsement is expected on Friday, Romney aides said.
The online poll of 1,629 registered voters included 579 Republicans, 308 independents and 741 Democrats.
The precision of the Reuters/Ipsos online polls is measured using a credibility interval. In this case, the poll has a credibility interval of plus or minus 2.8 percentage points for all respondents. For Republicans it was plus or minus 4.7 points, independents 6.5 points and 4.2 points for Democrats.
For the 317 Tea Party supporters in the poll, the credibility interval was 6.4 percentage points.
(For a link to a poll graphic, please click on http://link.reuters.com/vam97s )
(Additional reporting by Steve Holland; Editing by Cynthia Osterman; Editing by Alistair Bell and Eric Beech)