The Obama campaign will begin airing a new TV ad Monday on network and cable in all 50 states. The ad is aimed at middle class voters, with a house being built in the background as a narrator speaks.

"Three-Bedroom Ranch":

UPDATE: The McCain campaign responds with a statement from senior policy adviser Doug Holtz-Eakin:

"Barack Obama has voted in support of higher taxes 94 times in just 3 years, including higher taxes for Americans making just $42,000 a year. If voters consider Barack Obama's record of opposing tax cuts and his outspoken proposals to raise taxes on family savings, Social Security and small businesses -- this latest campaign promise lacks a single shred of credibility."