WASHINGTON (AP) — Just a third of Americans back President Barack Obama's health care overhaul on which the Supreme Court is about to pass judgment, a new poll finds. But there is overwhelming support among both supporters and opponents for Congress and the president to begin work on a new bill if the high court strikes down the two-year-old law.

The overall level of support for the law is relatively unchanged in recent months, with 47 percent opposing it. But an Associated Press-GfK poll shows that only 21 percent of independents approve of the law, a new low in AP-GfK polling.

The Supreme Court is expected to rule on the 2010 law in the next week or so. Most of the law's major changes aimed at extending health insurance to more than 30 million Americans who now lack coverage have yet to take effect, including the requirement that most people have health insurance or pay a penalty. The insurance mandate has been among the least popular aspects of the law. Provisions that have gone into effect include extended coverage for young adults on their parents' insurance and relief for seniors with high prescription drug costs.