Sen. Sherrod Brown, D-Ohio, holds a significant lead over GOP Treasurer Josh Mandel, according to a new Quinnipiac University/CBS News/New York Times poll released on Thursday.
Brown leads Mandel 48 percent to 41 percent in the survey, and 10 percent of voters are undecided. In a late July poll conducted for Quinnipiac University/CBS News/New York Times, Brown held a slightly wider lead: 51 percent to 39 percent.
The two are close among independent voters, with Mandel at 43 percent support to Brown's 42 percent. Brown maintains a sizable lead among female voters, with 49 percent support compared to 37 percent support for Mandel.
Brown is being heavily targeted by Republican outside groups, which have already spent over $11.5 million targeting the senator.
Meanwhile, President Obama leads Mitt Romney 50 percent to 46 percent in the new poll -- the same margin he led by in the previous survey.
The poll was conducted from August 15 through August 21, surveying 1,253 likely voters with a margin of error of plus-or-minus 2.8 percentage points.