Washington (CNN) - If a rematch of the 2012 presidential election were held today, GOP nominee Mitt Romney would top President Barack Obama in the popular vote, according to a new national survey.
But a CNN/ORC International poll also indicates that if Romney changes his mind and runs again for the White House, Hillary Clinton would best him by double digits in a hypothetical showdown.
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The survey, released Sunday morning, also suggests that more Americans see Clinton as a strong and capable leader than those who feel the same way about Obama. But Clinton's numbers on five personal characteristics have slightly edged down the past few months.
And the poll points to a jump the past month in support among Republicans for New Jersey Gov. Chris Christie and Texas Gov. Rick Perry.
How Romney fares
According to the poll, if the 2012 election were somehow held again, Romney would capture 53% of the popular vote, with the President at 44%. Obama beat Romney 51%-47% in the popular vote in the 2012 contest. And he won the all-important Electoral College by a wider margin, 332 electoral votes to Romney's 206.
Last November, an ABC News/Washington Post survey indicated that if the 2012 election were held again, Romney would have had a 49%-45% edge over Obama in the popular vote.
Romney has said numerous times that he won't run for the White House again. But what if things changed and he ended up as the GOP nominee in 2016? The CNN poll indicates that 55% of Americans would support Clinton, with Romney at 42%.
"Politically speaking, there is an interesting group of people who would not vote for Obama but would pick Clinton over Romney," said CNN Polling Director Keating Holland. "It turns out that nearly seven in ten of them are women, and 56% are Independents."
The CNN poll – just like almost every national and state survey preceding it – indicates that the former secretary of state remains the overwhelming frontrunner for the Democratic nomination. Clinton is seriously considering a second White House run.
Two-thirds of Democrats and independents who lean toward the party say they would most likely support Clinton for the presidential nomination. One in ten say they'd back freshman Sen. Elizabeth Warren of Massachusetts, a super star among liberals. And eight percent support Vice President Joe Biden. That's a slight swap from last year, when Biden stood at 12% and Warren at 7% in CNN polling.
Like Clinton, Biden is mulling another presidential bid, while Warren has said numerous times that she's not running in 2016.
Did book tour hurt Clinton?
The poll was conducted more than a month into Clinton's book tour for her new memoir "Hard Choices."
Did Clinton's well publicized book tour – including her controversial remarks that she and her husband Bill Clinton were "dead broke" when they left the White House in 2001 – hurt her standing with the public?
The number who say that Clinton shares their values dropped from 56% in March to 51% now, and the number who say she cares about people edged down from 56% to 53% in the same time period.
"But it's tough to tell whether Clinton's remarks were the reason for any change that might have happened. The number who believe that Clinton agrees with them on issue and can manage the government effectively also dropped, and those are not qualities that you would expect to be affected by any concerns over Clinton's wealth," said Holland. "The more likely explanation is that the book tour hurt Clinton - if it did so - not because of any specific comments that she made but because more Americans now view her as an active candidate for the White House."
GOP field all knotted up, but big jumps for Christie and Perry
The poll also indicates the race for the 2016 GOP nomination remains a wide open contest with no obvious frontrunner among the potential Republican White House hopefuls.
Thirteen percent of Republicans and independents who lean towards the GOP say they'd likely back Christie, with Sen. Rand Paul of Kentucky and former Arkansas Gov. Mike Huckabee, a 2008 Republican presidential candidate, each at 12%. Perry – who ran for the White House last time around – and Rep. Paul Ryan of Wisconsin – the 2012 GOP vice presidential nominee – are both at 11%.
Christie and Perry have each jumped five percentage points from CNN's last Republican nomination poll, which was conducted in June.
Former Florida Gov. Jeb Bush and Sen. Ted Cruz of Texas are both at 8%, with Sen. Marco Rubio of Florida at 6%, Gov. Scott Walker of Wisconsin at 5% and former Sen. Rick Santorum of Pennsylvania, who battled Romney deep into the 2012 GOP primary calendar, at 3%.
Turnout key in midterms
The poll's release comes with 100 days to go until November's elections. And the biggest question surrounding this year's midterms is how many people will turn out to vote.
The answer is crucial, because a smaller, more typical midterm electorate should favor the Republican Party. That's because single women, and younger and minority voters, who are big supporters of Democrats in presidential election years, tend to cast ballots in smaller numbers in the midterms.
That's the problem facing Democrats this November, as they try to hold onto their 55-45 majority in the Senate (53 Democrats and two independents who caucus with the party). The party is defending 21 of the 36 seats up this year, with half of those Democratic-held seats in red or purple states. In the House, the Democrats need to pick up an extremely challenging 17 Republican held seats to win back the majority from the GOP.
The new CNN poll illustrates the turnout problem for the Democrats.
In the generic ballot question, the Democrats have a four percentage point 48%-44% edge over the Republicans among registered voters. The generic ballot asks respondents to choose between a Democrat or Republican in their congressional district without identifying the candidates.
But when looking only at those who say they voted in the 2010 midterms – when the GOP won back the House thanks to a historic 63-seat pick up and narrowed the Democrats' control of the Senate – Republicans hold a two-point 48%-46% margin.
The poll was conducted for CNN by ORC International from July 18-20, with 1,012 adult Americans questioned by telephone. The survey's overall sampling error is plus or minus three percentage points.