A few caveats are in order before considering the details of this new poll.  The media outlet that commissioned it, InsideMedford.com, looks like blog, but its articles appear to avoid any opinion tilt at all.  The pollster is not a well-known outfit, but the report says they work with Harvard’s Kennedy School Center for Public Leadership — an irony in itself.  The poll was conducted by telephone IVR, which has its advocates and detractors.

With the stage set, the results will certainly please Scott Brown’s backers — and also corroborates what I noted earlier about turnout modeling:

A poll conducted by the Merriman River Group (MRG) and InsideMedford.com indicates that Scott Brown leads Martha Coakley 50.8% – 41.2% in the contest to fill the seat of the late Senator Ted Kennedy. Liberty Party candidate Joe Kennedy pulls in just 1.8% support, while 6.2% of voters are still not sure. Brown and Coakley both have most of their supporters locked in. 98% of both candidate’s supporters say they are definitely or probably going to vote for their candidate. In contrast, 22% of Kennedy’s supporters are just leaning toward him, suggesting that Brown and Coakley may both want to take aim at swaying those voters.

Not surprisingly, nearly all of Coakley’s supporters approve of President Obama’s job performance, while three-quarters of Brown’s supporters disapprove. Coakley may see a glimmer of hope in the fact that more than two-thirds of undecided voters approve of the president’s job performance while only 6% disapprove, especially in light of the president’s swing through the state to campaign for her later today.

The poll’s sampling looks a lot more realistic than ARG’s from late last week as well.  The D-R-I split in this poll is 34-17-48, giving Democrats a more realistic +17 partisan advantage.  Plugging that split into ARG’s responses produces 50.62% support for Brown, and 42.07% for Coakley, or a lead of 8.35%.  That’s within the margin of error in both polls, and reinforces my earlier analysis on the effect of turnout models on polling.

One interesting internal from this poll: Coakley and Brown split the women’s vote, 46% each.  Brown has a 30-point advantage with men, a 30-point advantage among self-professed moderates, and a 20-point advantage among voters younger than 45.  Any one of those findings are shocking in major races in or out of Massachusetts, but all of them put together spells disaster for Democrats, and not just in this special election.