Mitt Romney has opened up a lead in Florida, a must-win state for the Republican presidential nominee, according to a new poll released late on Thursday. The poll, conducted by Mason-Dixon Polling & Research for the Miami Herald, Tampa Bay Times, the Spanish-language El Nuevo Herald, and two in-state cable news stations, shows a significant swing in Romney's direction following last week's debate, but its results are at odds with another poll released less than 24 hours ago that showed the race tied.
Romney leads President Obama in the new survey, 51 percent to 44 percent, with 5 percent of likely voters undecided or preferring one of the other party tickets. In the previous poll, conducted in mid-September, Obama held a statistically-insignificant, 1-point advantage, 48 percent to 47 percent.
The new poll, which surveyed 800 likely voters and carries a margin of error of plus-or-minus 3.5 percentage points, shows big swings towards Romney among whites, Hispanics, and independents. White voters now prefer Romney by a 27-point margin, 61 percent to 34 percent. Last month, he led by 15 points among whites, 55 percent to 40 percent.
Among Hispanics, the two candidates now run neck-and-neck, 46 percent for Romney, and 44 percent for Obama. That compares to a 9-point Obama lead in mid-September.
Voters who identify with neither party swung 24 percentage points, the poll shows. Obama led by 11 points among independents last month, but Romney now holds a 13-point margin among this group, 52 percent to 39 percent.
Obama's job approval rating fell, from 47 percent last month to 44 percent now. The percentage who disapprove of his job performance shot up to 54 percent, from just 45 percent last month.
Meanwhile, the poll shows the debate afforded Romney the opportunity to create a positive impression. Half of likely voters now view him favorably, up from 43 percent last month. The percentage viewing him unfavorably was virtually unchanged.
Romney is now the more trusted candidate when it comes to the economy and foreign policy, the poll shows. Romney is also viewed as more trustworthy, and as the candidate who will look out for the middle class. A significant majority of likely voters say Obama's plans are more likely to do "long-term harm to Medicare" than Romney's, 54 percent to 40 percent.
The Mason-Dixon poll, which was conducted Oct. 8-10, differs significantly from an NBC News/Wall Street Journal/Marist poll conducted mostly concurrently and also released on Thursday, which showed the two candidates neck-and-neck: Obama at 48 percent, to Romney's 47 percent.
In that poll, Romney led by 19 points among whites, while Obama edged him among Hispanics by 2 percentage points. Independents broke for Romney in the Marist poll by a 5-point margin.
Romney holds a slight, 3-point edge on the economy in the Marist poll, but Obama holds a 9-point advantage on foreign policy and is preferred by 8 percentage points on the issue of Medicare.