A major union has invested almost $1 million in a radio ad targeting Missouri Senate candidate Roy Blunt (R) for his 2007 vote against raising the federal minimum wage.

"He's been in Washington for 14 years, and he gets paid a $170,000 every year," the announcer says in the minute-long spot. "So, he's pocketed a couple of million dollars since he went to Washington."

The announcer goes on to say Blunt has voted to raise his own pay five times, "but when he had a chance to raise the minimum wage, Congressman Blunt voted no. … He's really out of touch."

The American Federation of State, County and Municipal Employees (AFSCME) spent $700,000 on the ad, according to a Federal Election Commission filing.

It started airing Friday statewide on more than 200 radio stations outside the St. Louis and Kansas City media markets, according to a union spokesman.

The Blunt camp is asking stations to pull the ad, noting a Springfield station already had.

"Missouri broadcasters have been advised that this is a deceptive and false advertisement that should be pulled from the airwaves immediately," Rich Chrismer, a spokesman for Blunt, said in a statement. "As Robin Carnahan and AFSCME should know, the 27th Amendment to the United States Constitution prohibits members of Congress from voting to increase their own pay."

Members get an automatic cost-of-living increase calculated by the Bureau of Labor Statistics unless they vote against receiving it. The House has already voted to freeze its pay through 2011.

Meanwhile, the Blunt camp is pushing other stations to take down the ad.  

"We encourage Missouri broadcasters to review the content of the ad, review the U.S. Constitution, get the facts and join KTXR in pulling this advertisement," Chrismer said.

Democrats and their union allies used the minimum wage issue against Republicans effectively in 2006 — particularly in the Midwest. In Iowa, for instance, Democrats were able to use raising the minimum wage as a wedge to help them pick up two House seats and the governor's mansion.

Blunt faces Democrat Robin Carnahan in November.

--Updated at 11:27 a.m.