WASHINGTON (AP) — Amid a budget debate that will affect the health care of virtually every family, a new poll finds support for President Barack Obama's overhaul at its lowest level since passage last year.

But in a ringing defense of Obama's policies, Medicare chief Donald Berwick pleaded Tuesday for more time on the health care law, and branded a leading Republican plan "unfair and harmful" and "a form of withholding care."

The Associated Press-GfK poll showed that support for Obama's expansion of health insurance coverage has slipped to 35 percent, while opposition stands at 45 percent and another 17 percent are neutral. That nearly ties the previous low in September 2009, when after a summer of heated town hall meetings dominated by critics, only 34 percent supported Obama's approach.