Sen. Joe Lieberman reaffirmed his pledge Wednesday to withhold his vote for the Senate's sweeping health care reform bill if it includes a so-called "public option," saying a government-run plan is "unnecessary" and threatens to drive up costs for taxpayers.

"It's not free," the Connecticut senator told Fox News on Wednesday.

Lieberman, an Independent Democrat, said a day earlier that he would back a Republican filibuster against Senate Majority Leader Harry Reid's health care reform bill if a government-backed insurance plan remains in the package. He warned Wednesday that the plan would have several negative side effects...