Warren leads in Boston Globe poll

The rallying of Massachusetts Democrats around Elizabeth Warren produces another bracing poll result for Sen. Scott Brown, via the Boston Globe:

Warren, a Democrat, leads Brown, a Republican, 43 percent to 38 percent, a shift from the Globe’s last poll in May, when Brown held a 2-point lead. But the race remains within either candidate’s grasp, with 18 percent of voters still undecided, said Andrew E. Smith, the Globe’s pollster and the director of the University of New Hampshire ­Survey Center. ... Warren’s lead is within the poll’s margin of error of plus or minus 4.4 percent, meaning a spread of as much as 8 percentage points between the candidates would still statistically count as a dead heat. Still, the survey is sobering for Brown six weeks before the election. “It’s trending away from Brown,’’ said Smith. “Brown right now is not doing well enough among Democrats to offset the advantage that ­Warren has,” said Smith. “That’s just such a big obstacle to overcome for any Republican candidate” in Massachusetts.

With the exception of a Boston Herald poll, Warren has led every major survey since the Democratic National Convention, and Brown heads into the final month of the election under pressure to refocus the race on something other than big-picture partisan and ideological debates.

Of all the forces driving Republican pessimism about flipping control of the Senate, Brown's changing fortunes are one of the big ones. If Mitt Romney were to win the presidential election and Paul Ryan were able to cast a tie-breaking vote in the Senate, it's relatively easy to see how Republicans could take the majority by winning three seats. If Romney loses, a four-seat gain becomes harder; and if both Romney and Scott Brown lose, that may be a burden too great for Senate Republicans to overcome.