A new poll finds support for President Barack Obama's overhaul at its lowest level since passage last year.
Worries about government deficits that keep rising due to health care costs appear to be driving the numbers.
The Associated Press-GfK poll showed that support for Obama's health insurance expansion has slipped to 35 percent, while opposition stands at 45 percent, and another 17 percent are neutral.
Among seniors, support has dipped below 30 percent for the first time.
But in an interview Tuesday with the AP, Medicare chief Donald Berwick pleaded for more time on the health care law. And he branded a leading Republican plan "unfair and harmful" and "a form of withholding care."
The poll comes ahead of a major speech by Obama on the deficit, scheduled for Wednesday.