Updated at 11:37 a.m.
Sen. Scott Brown, R-Mass., leads Democrat Elizabeth Warren by a 53-28 percent margin among likely 2012 voters, according to a poll conducted for the senator and the National Republican Senatorial Committee.
Matched against Warren, who was passed over for the top job at the Consumer Financial Protection Bureau in the face of GOP resistance and is considering a Senate run, Brown leads by a 25-point margin, with 18 percent undecided. He leads Newton Mayor Setti Warren, 57-21, and City Year co-founder Alan Khazei, 54-24.
Two-thirds of likely Massachusetts voters approve of Brown's job performance and 56 percent say he deserves reelection, according to the survey.
The Public Opinion Strategies poll showed Brown with a 62 percent favorable and 28 percent unfavorable rating; his favorables are six points higher than during his Jan. 2010 election. His job performance rating has climbed six points since April 2010.
The poll also shows that 60 percent of voters thought Brown, who ran promising to vote free of party orthodoxy, had been an "independent vote" in the Senate rather than asserting partisan interests ahead of the state's. Thirty-one percent said it had been the other way around.
Democratic Senatorial Campaign Committee spokesman Matt Canter said in a statement, "The only percentage that will matter to Bay Staters next November is that Scott Brown votes with extreme Republicans in Washington nearly 90 percent of the time. Not only does this month-old poll contradict other polls that show Brown's popularity slipping, but the simple fact that national Republicans feel the need to release it reeks of desperation and fear that Scott Brown is very vulnerable."
Conducted June 21-23, the poll included interviews with 500 likely 2012 voters and carries an error margin of plus/minus 4.4 percent, according to a memo from the polling firm.