Mayor Mike McGinn is down 22 points:

The poll of 503 likely Seattle voters finds 52 percent said they would vote for state Senator Ed Murray over McGinn, 52 percent to 30 percent, if the election were held today. Eighteen percent were undecided.

The poll, conducted by SurveyUSA over the weekend, also found that 40 percent of 652 registered voters approve of the job McGinn is doing while 44 percent disapprove.

Murray has a 57 percent approval rating and 19 percent disapproval.

Obviously, this is an impressive lead for Murray and a potentially unwinnable position for McGinn. At roughly this point in the mayor's race four years ago, the candidates were tied with 38 points each, and McGinn took only a narrow victory in November.

The Murray campaign sent out a happy-dance e-mail to reporters this morning that maintained their talking point that Murray brings people together and McGinn pushes them apart, saying, "Seattle voters are responding positively to Ed's message of providing effective, collaborative, progressive leadership (as opposed to the current divisive approach from Mayor McGinn)." They also played down expectation of a blowout on the ballot. [W]e also anticipate the race to be significantly closer than these numbers would indicate," the Murray campaign said. "So we would caution the media to take these numbers with a grain of salt."

Polls are only polls and this is still September etc., but this poll seems to repeat a trend among voters that we saw with Democratic Party activists earlier this year: If they didn't support McGinn at first, they won't. They'll pick anyone but him. Both men got about 30 percent of the primary election vote, but while Murray now appears to be picking up support, McGinn looks stuck with his base. In this case, the primary voters who went for Bruce Harrell and Peter Steinbrueck all seem to be flocking to Murray or remaining undecided. And whatever message McGinn has delivered, it's not persuasive or reaching them at all.