Washington (CNN) - It's amazing what back to back wins can do for your poll numbers.
One-time Republican presidential front-runner Mitt Romney is back on top in the race for the GOP nomination, according to a new national survey.
A CNN/ORC International poll, conducted on Wednesday and Thursday after the New Hampshire primary, also indicates that the former Massachusetts governor's support nearly doubles in hypothetical one-on-one match-ups against his strongest rivals.
According to the survey, 34% of Republicans and independents who lean towards the GOP say they're likely to support the former Massachusetts governor for the nomination, with former House Speaker Newt Gingrich at 18%, and Rep. Ron Paul of Texas and former Sen. Rick Santorum of Pennsylvania each at 15%. Texas Gov. Rick Perry stands at 9% in the poll, with former Utah Gov. and former ambassador to China Jon Huntsman at 4%.
Romney and Gingrich were tied at 28% support in CNN's last national survey, which was conducted in mid-December, before Romney's narrow victory in last week's Iowa caucuses and his big win Tuesday night in the New Hampshire primary. Romney became the first non-incumbent to win Iowa and New Hampshire back to back.
Gingrich finished out of the money in Iowa and New Hampshire. Romney edged up six points while Gingrich dropped ten points since the last poll. Paul, who came in third in Iowa and a strong second in New Hampshire, has inched up a point, while Santorum, who lost to Romney by just eight votes in Iowa before coming in fifth in New Hampshire, is up 11 points.
"Romney's increased support has come entirely from conservative Republicans, and mostly at Gingrich's expense. Romney has actually lost support among moderate Republicans," says CNN Polling Director Keating Holland. "And most of Romney's newfound strength has come among higher-income categories - he has gained only three points among GOPers with less than $50,000 but 11 points among those who make more than that amount."
The poll also looks at hypothetical two-man matchups for the GOP nomination, with Romney leading Gingrich 59-37%, beating Santorum 60%-37%, and topping Paul 67-31%.
But Romney is certainly not unstoppable. Only 37% say they definitely will support the candidate they are currently backing, with 56 percent saying they might change their mind.
And the poll indicates Romney has some weaknesses.
Paul, for example, is a little bit ahead of him when Republicans are asked which candidate cares most about people. Gingrich tops Romney when Republicans are asked to name the candidate who is most qualified to be Commander-in-Chief.
But Romney continues to have one ace up his sleeve - electability. Seven in ten Republicans say that they prefer a candidate who can beat Obama to one who agrees with them on every issue, and 55% believe that Romney has the best chance of defeating Obama in the general election.
"That's the biggest advantage of winning a race, such as Iowa or New Hampshire. Candidates who have won something look like winners; candidates who lost look like losers," says Holland. "Iowa and New Hampshire are probably a major reason why the number of Republicans who think Romney can beat Obama rose by 19 points since December while the number who think Gingrich has the best chance in November dropped by nearly two-thirds in that time."
The poll was conducted for CNN by ORC International, with 1,021 adult Americans, including 449 Republicans and independents who lean Republican, questioned by telephone. The survey's sampling error is plus or minus 4.5 percentage points.