U.S. Health Care Reform Act
The Obama administration has postponed a deadline in the Affordable Care Act for employers to provide all full-time workers with healthcare until 2015. REUTERS

More Americans believe that the U.S. Supreme Court will strike down the health care law's insurance mandate, though the justices' decision will be based on ideology instead of legal analysis, according to a poll released Thursday.

The poll from the Kaiser Family Foundation showed the American public is divided over the President Barack Obama's Affordable Care Act and its fate before the U.S. Supreme Court, which will hear challenges to the law in late March.

On the individual mandate, the centerpiece of the health care law, 55 percent of Americans believe that the high court will strike it down. An almost equal amount say the justices should find the mandate unconstitutional, while 29 percent believe the mandate will survive the challenge.

Even if the mandate goes down, a majority of Americans still believe the Affordable Care Act will stand at the end of the day. Less than a third believe the entire law will fall with the mandate.

That issue, known as severability, is one of several that the Supreme Court justices will consider when hearing arguments over the Affordable Care Act. Critics of the law believe the individual mandate is crucial to the survival of the health law. The Obama administration, meanwhile, somewhat agrees, arguing that some of the law's provisions cannot stand without the mandate.

In a glimpse of what Americans think about the nine Supreme Court justices, 59 percent say ideology will be the deciding factor in determining the constitutionality of the mandate, compared to 28 percent who believe a decision will be based on the law. That sentiment extends to the justices in general. Three-quarters of Americans believe that Justices let ideology influence their legal decisions.

In the run-up to the Supreme Court showdown over the health care law, Obama's biggest domestic policy achievement, Americans are sour on the law.

Less than half -- 44 percent -- disapprove of the law, which has 37 percent approval. The mandate remains by far the most unpopular part of the health care law: two-thirds disapprove of a requirement for most Americans to obtain health insurance, while 30 percent back the mandate.

Still, that does not bode well for Republicans who have championed a full repeal of the Affordable Care Act and have made it an election year issue in the presidential campaign. Almost a third of Americans want the health care law expanded, while 19 percent want it left in its current state.

More than a fifth of the U.S. want the Affordable Care Act appealed outright but even a lesser amount, 18 percent, want an alternative from the GOP.

The Kaiser Family Foundation's poll surveyed 1,206 adults on land lines and cell phones from Jan. 12-17, with a three-point margin of error.