AP: Obama has lost six points in three weeks among likely voters

Take this, as with all polling this cycle, with a grain of salt — but usually the error in the AP polling goes the other direction.  A new poll of likely voters has Barack Obama clinging to a one-point lead, 44%-43%, with John McCain making up almost all of a seven-point deficit over the last three weeks.  Guess what may have done the trick, according to the AP?

An Associated Press-GfK poll shows the presidential race tightened after the final debate, with John McCain gaining among whites and people earning less than $50,000. Two weeks before the election, McCain and Barack Obama are essentially running even among likely voters.

The poll put Obama at 44 percent and McCain at 43 percent among those voters who are considered likely to vote on Nov. 4. The survey supports what some Republicans and Democrats privately have said in recent days: that the race has narrowed as Republicans drift home to their party. McCain’s “Joe the plumber” analogy also seemed to strike a chord.

There’s still plenty of time left in this election.  McCain has now obviously found a winning message that negates Obama’s economic populism.  These respondents hadn’t yet heard Joe Biden’s warning about Obama’s election provoking an international crisis to test his mettle, another message that will regenerate doubts about voting for a man with no executive or military experience in the middle of a war.

The news isn’t great, but there isn’t any need for despair, either.  McCain and Palin need to keep pressing the attack on Obama’s redistributionism and inexperience.

Update: Mary Katharine Ham notes a particularly interesting aspect to this poll:

A significant number of the interviews were conducted by dialing a randomly selected sample of cell phone numbers, and thus this poll had a chance to reach voters who were excluded from some other polls.

Cell-phone users are supposed to be left-leaning demographic historically missed by pollsters (though the vast unpolled cellular herd has never been vast enough to change the game on Election Day). Why would McCain be gaining in a poll with cell-phone users included, and if he is, isn’t it exceedingly promising for the Republican candidate that the numbers are this close? Perhaps they’re polling a disproportionate number of “push-to-talk” Nextel users (read: Joe the Plumber and Tito the Construction Worker) and undersampling Sidekick users.

I’d call that very promising.