A new CNN/ORC poll has President Obama leading Mitt Romney 52 percent to 46 percent among likely voters. That's a dramatic shift from the news organization's poll a week ago, which had the two candidates tied at 48 percent.
Obama generally struggles more in polls of likely voters than surveys of registered voters. In the last CNN/ORC poll, Republicans were more enthusiastic than Democrats about voting; now both parties are about equal in their enthusiasm. But independents lean towards Romney by 14 points.
In a memo Monday morning, Romney pollster Neil Newhouse argued that surveys showing Obama leading Romney can be attributed to a convention bounce, a "sugar high" that will fade. Convention bounces are often short-lived; polling right after conventions is volatile. But Nate Silver has suggested that the shift towards Obama could last through the election.
The CNN/ORC poll has a margin of error of plus or minus 3.5 percentage points.