Just days before voters head to the polls for the June 3 primary, an independent expenditure is hitting the television airwaves with an advertisement slamming state Senate candidate Mark Leno on the issue of education.

“San Francisco Assemblyman Mark Leno Claims that he's for better schools,” an announcer says in the 30-second spot. “Yet in 2004, it was Leno who joined Republicans, and with one vote to spare, cut $3.1 billion from California schools. San Francisco and the North Bay lost $75 million in school funding. Leno's explanation: ‘Cutting the schools' money was the best deal we could get and I didn't lose my committee chairmanship.’ Mark Leno: Not exactly a profile in courage.”

The Sacramento Bee is reporting that the organization releasing the ad, called “Protect our Kids,” is spending $45,000 on the spot.

The California Teachers Association, which has endorsed Leno, quickly issued a statement in Leno’s defense.

"Mark Leno is a strong friend of our public school teachers and students. He has never failed to stand up for our schools, and he has always fought for educators and students at the local and state levels," said CTA President David Sanchez, according to the Bee.

Leno, a state Assemblyman, has come under withering attack from Democratic primary rival Joe Nation, a former state Assemblyman, on education. Last week Nation’s campaign sent out a mailer throughout the Marin, San Francisco, and Sonoma-area district hitting Leno for the same vote mentioned in the Protect our Kids ad.

Leno, Nation, and incumbent Carole Migden are facing off in a primary for the District 3 state Senate seat.