The Reason-Rupe poll of 1,200 U.S. adults found 62 percent said the Affordable Care Act was unconstitutional.
The poll also found 87 percent of U.S. adults said Congress does not have the power to require the purchase of broccoli as some legal experts have suggested would be the case if Congress can require individuals to buy healthcare insurance.
Eight percent said Congress cannot force a person to buy vegetables.
When it comes to addressing their healthcare needs, just 23 percent of Americans trust the government. That's less than half of the 50 percent who say they trust health insurance companies and considerably lower than the 84 percent who trust their doctors.
Reason-Rupe found 23 percent of U.S. adults trust the government, yet 67 percent of Americans said public sector workers have better healthcare benefits than private sector workers, 22 percent said the benefits were about the same and 4 percent said private sector workers get better benefits than government workers.
The survey also asked about organ donation. Fifty-five percent said healthy adults under medical supervision should be allowed to sell their own organs, while 34 percent opposed the sale of organs.
The poll was conducted for Reason Foundation -- often described as libertarian -- by NSON Opinion Strategy March 10-20. The poll has a margin of error of 3 percentage points.