The Fix reports

Mitt Romney has opened up a slight lead on President Obama in the 12 most competitive states in the country, according to a new poll from USA Today and Gallup.

The poll shows Romney at 51 percent among a sample of likely voters in the 12 states, while Obama is at 46 percent.

In response, Obama's campaign has questioned the poll's methodology. In a memo, campaign pollster Joel Benenson called the survey "an extreme outlier, defying the trends seen in every other battleground and national poll." 

In past weeks, it was more often Republicans who were questioning polls that showed Obama in the lead.