Right after the August primary, the KING 5 tracking poll found Republican Dino Rossi was ahead. But Democratic incumbent Patty Murray has been gaining ground and in our latest poll, it's effectively a dead heat with 50% telling SurveyUSA they now favor Murray; 48% Rossi.

In the poll of 609 likely statewide voters, 3% were undecided; the poll's margin of error is +/-4.1%.

In the world of the KING 5 tracking poll (a "tracking poll" that only comes out once a month or so), this represents a sudden nine-point swing in Murray's favor since August. If you've been watching other polls, however, you've known for about a week that Murray was ahead.

Here's the most interesting KING 5 finding, to me: Rossi leads among voters under the age of 50. I'm interested to know more about how his lead looks among different segments of the under-50 vote, but it's clear that Rossi's campaign thinks it can grab a lot of votes from this demographic; I saw his latest anti-Murray ad while watching the season opener of Glee.