Updated

American voters are about evenly divided over how the U.S. Supreme Court should decide the constitutional challenge to President Obama’s health care reform law.

The Supreme Court begins hearing oral arguments in the case on March 26.

A Fox News poll released Thursday found 46 percent want the nation’s high court to overturn the law, while 43 percent think it should uphold the Patient Protection and Affordable Care Act.

Click here for full Fox News poll results.

A year ago, by a 49-42 percent margin, voters wanted the law invalidated as unconstitutional (April 2011).

All four current Republican presidential candidates say they support legislation repealing President Obama’s signature first-term legislative achievement.

Meanwhile, more voters disapprove (52 percent) than approve (43 percent) of the job Obama is doing on health care. His ratings on this issue have remained mostly unchanged for the last year.

A majority of voters wants Congress to repeal at least part of the health care law: 31 percent favor complete repeal and another 28 percent would like lawmakers to repeal parts of it.

A few voters -- 14 percent -- want lawmakers to leave the law in its current form. One voter in four (22 percent) would like to see it expanded. That’s up from 18 percent who felt that way last year (April 2011).

Most Republicans want lawmakers to repeal all (56 percent) or parts (31 percent) of the law.

While few Democrats -- 7 percent -- think the health care law should be repealed entirely, about one in four (23 percent) would repeal some of it.

Most Democrats want the law expanded (39 percent) or left as is (24 percent).

A 63-percent majority of independents wants at least some of the law repealed.

The Fox News poll is based on land line and cell phone interviews with 912 randomly-chosen registered voters nationwide and was conducted under the joint direction of Anderson Robbins Research (D) and Shaw & Company Research (R) from March 10 to March 12. For the total sample, it has a margin of sampling error of plus or minus 3 percentage points.