Brown's image rating over that time has remained constant: 55 percent have a favorable opinion, and 30 percent view him favorably, compared to a 54 percent/29 percent split in late March. Seven-in-ten likely voters say they are at least "somewhat aware" of the controversy surrounding Warren's heritage, though, overall, 72 percent of voters (including more than half of Brown supporters) say it will have no impact on their vote. (Notably, the poll was conducted over an extended time period, from May 25-31. Warren acknowledged for the first time late on May 30 that she told Harvard University and the University of Pennsylvania that she was Native American, meaning that the vast majority of interviews were conducted prior to this admission.) Warren will likely be buoyed by the presidential race in the Democratic bastion, even if former Republican Gov. Mitt Romney has narrowed the race somewhat. President Obama leads Romney, 46 percent to 34 percent, with 19 percent undecided or preferring another candidate. Two months ago, Obama led Romney by a 16-point margin in the Bay State. Brown wins just 8 percent of voters who say they will vote for Obama in the presidential election, but he holds a more than two-to-one advantage among those still undecided on the top of the ticket. The poll surveyed 651 likely voters via landline and cellular telephone.