"It's a bad idea to use public money to spend on private academies," said Utah's only Democratic national office holder. "I'm telling people to vote against it."

Utah's voucher program, which would be the most comprehensive in the nation, faces a referendum Nov. 6.

Republicans Gov. Jon Huntsman Jr., Congressman Rob Bishop and GOP legislative leadership have endorsed it.

Matheson says he agrees with encouraging educational innovation and giving parents choices, but vouchers won't accomplish that.

"That's not what this is about," he said. "This is about taking public taxpayers' funds out and putting them into private schools."

Guaranteed public education is one of the great traditions America and Utah, he said.

"It has produced an educated population that has made us a super power. As we now face the challenges of the global economy, this is not the time to be taking resources from the public education system. That would be a mistake."