(CNN) – A majority of Americans don't believe the explanations by New Jersey Gov. Chris Christie and former Secretary of State Hillary Clinton about two controversies that continue to dog them as they seriously consider White House runs, according to a new national poll.
And another new survey indicates Clinton topping Christie by double digits in one of the most important states in the race for the White House.
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Sixty-three percent of Americans questioned in a new Bloomberg National Poll say they don't believe the Garden State's Republican governor when he said he knew nothing about the George Washington Bridge controversy.
Christie's administration is facing both federal and state investigations over allegations that some of his aides closed access lanes to the nation's busiest bridge last September to punish the mayor of Fort Lee, New Jersey, for not endorsing Christie's re-election. The governor has denied knowing anything about the gridlock until after it occurred and has said he knew nothing about any political mischief by members of his administration. But the controversy has put a cloud over Christie's political future.
By a 51%-41% margin, the poll indicates the public doesn't believe the former secretary of state when she says she never saw requests for more security at the U.S. diplomatic compound in Benghazi prior to the September 2012 attack that left the U.S. ambassador to Libya and three other Americans dead. Some Republicans have hammered Clinton over her handling of the incident.
While Clinton's favorable rating among Americans has slightly edged down from 58% last May to 56% now, the survey indicates Christie's favorable rating has fallen from 50% in June to 32% now.
According to the poll, half of Americans want Clinton to launch a second bid for the White House, with just a quarter saying they would like Christie to run for president. And if the 2016 election were held today with Clinton as the Democratic nominee and Christie as the GOP nominee, the poll indicates Clinton topping Christie 52%-39%.
Clinton makes gains against Christie in Iowa
According to a new Quinnipiac University poll released Thursday, 48% of registered voters in Iowa say they would back Clinton in 2016 if she were the Democratic Party's nominee, with 35% saying they'd support Christie if he were the GOP nominee.
That's a change from Quinnipiac's last Hawkeye State poll, in mid-December, when Christie had a five-point 45%-40% edge over Clinton in the hypothetical battle for Iowa's six electoral votes. Since then, of course, the bridge controversy went viral, landing in the national headlines for weeks in January and February.
The Quinnipiac poll indicates Clinton also holds double digit leads over three other possible GOP presidential contenders in 2016: Sen. Rand Paul of Kentucky, Sen. Ted Cruz of Texas and former two-term Florida Gov. Jeb Bush.
Iowa holds an important spot in presidential politics, as its caucuses kick off the caucus and primary calendar. But the state also plays an important role in general elections, as it's considered a closely watched swing state with six electoral votes up for grabs. President George W. Bush narrowly carried the state in his 2004 re-election victory. Then-Sen. Barack Obama won Iowa by 10-percentage points over Sen. John McCain in 2008. Obama carried the state by a smaller six point margin in his 2012 re-election.
Clinton's dominance in the new Iowa poll comes as Obama's approval rating in the Hawkeye State remains below 40%.
"Politics is a team sport and the head of the blue team, President Barack Obama, isn't doing well in the eyes of Iowans. But that doesn't seem to be hurting teammate Hillary Clinton who swamps potential 2016 Republican competitors among the same electorate," said Peter Brown, assistant director of the Quinnipiac University Poll.
The Quinnipiac University poll was conducted March 5-10, with 1,411 registered voters in Iowa questioned by telephone. The survey's overall sampling error is plus or minus 2.6 percentage points.
The Bloomberg National Poll was conducted March 7-10, with 1,001 adults nationwide questioned by telephone. The survey's overall sampling error is plus or minus 3.1 percentage points.