Chris Cillizza of the Washington Post reports on a major ad buy by a third-party group, The American Future Fund, on behalf of GOP senate candidate Scott Brown:

“Call Martha Coakley and tell her we can’t afford more taxes,” urges the ad’s narrator. The commercial, which will cost the group $400,000 for a five-day statewide buy, is the first of several planned ads hitting Coakley in advance of her Jan. 19 special election race against state Sen. Scott Brown, according to a source familiar with AFF’s strategy. The ad buy is welcome news for Brown who has been drastically outraised by Coakley and will be outspent badly on television in the closing days of the campaign. The AFF ads land as the race has begun to draw some national attention for the fact that some within the GOP believe Brown might be able to win.

Well, yes he might. If the margin is really only two points among those certain to vote, this is hardly in the bag for Coakley. And in fact, she’s had to go on the air with her own ads, a sign that those polls are narrowing. Cillizza remains skeptical that Brown can win, and in a Massachusetts race to fill Ted Kennedy’s seat, there is good reason to be so. But then he gives away the game: “Margin may matter here; Republicans will almost certainly declare victory if Brown loses by single digits.” Indeed they will, given that Obama won the state in 2008 by a 62 to 37 percent margin.

Brown has made the race a referendum on Obama’s policies; the Democrats are having a run of retirements; the GOP is basking in reports of good recruitment; and the media seem poised for a new storyline (“Is Obama in trouble?”). This means a close race is likely to be read as one more data point in the trend — further evidence of the Democrats’ political meltdown. (Cillizza notes Charlie Cook now puts the chances at 50-50 of the Democrats’ numbers sinking to 55 in the Senate.) So, yes, Brown could in fact win — and the GOP can win by losing.