Updated with comment from Murray campaign

As Politico reports this morning, the conservative American Action Network is launching a TV ad campaign against Democratic incumbent Sen. Patty Murray.

The ad, with requisite menacing music and sneering narrator, tries to turn Murray's trademark "mom in tennis shoes" image against her.

It shows a woman in dirty tennis shoes stepping on the backs of a small businessman, woman and child while the female narrator complains of Murray's votes for higher federal spending and taxes. The spot closes with the line: "Sorry Patty, it's time you got off our backs."

The American Action Network is a Washington D.C. political nonprofit that calls itself an "action tank" promoting "center-right" policies.

While it doesn't name any of Murray's rivals in the ad, the group has a connection to Murray's leading Republican challenger, Dino Rossi.

Its CEO is former Minnesota Sen. Norm Coleman. Rossi's campaign manager, Pat Shortridge, was a top aide for Coleman's unsuccessful reelection bid in 2008.

Politico reports the group intends to spend $750,000 on the campaign in Washington State, making it the first statewide blast in the Senate race by out-of-state political committees that are sure to sink millions of dollars into the high-stakes contest.

UPDATE Murray's campaign issued a statement blasting the ad as the work of Rossi's "corporate allies."

"As Washington state families struggle due to the reckless bets of Dino Rossi's Wall Street friends, his allies are spending three quarters of a million dollars to attack policies that help kids and workers," said Alex Glass, Murray's deputy campaign manager.