As the Supreme Court holds hearings this week on the fate of President Obama's health-care overhaul, polls indicate that two-thirds of Americans hope the justices will overturn at least parts of the law. And in a New York Times/CBS News poll, 47 percent of respondents say they oppose the law, while just 36 percent approve. (The rest had no opinion.) Why is there such resistance to "ObamaCare"? Here, four theories:

1. The individual mandate is poison
The American people want to see Obama's health care reforms "wiped from the books," says Peter Suderman at Reason, and the main reason is the law's individual mandate, which requires Americans to obtain health insurance. An ABC News/Washington Post poll released last week found that 67 percent of respondents want that part of the law removed. Even many people who otherwise like "ObamaCare" would rather "do away with the entire thing" than keep the whole law, mandate and all. Americans just can't stomach having the government order people to purchase coverage.

2. Republicans uniformly oppose it
It's obvious why at least half of the country hates "ObamaCare," says Joshua Green at Bloomberg Businessweek: The law is "the signature achievement" of Obama's first term, and that means the Republican Party is united against it. "Were the court to strike down the law, it would be a tremendous blow to Democrats."

3. The White House lost the messaging war
For years, says Dahlia Lithwick at Slate, all Americans have heard is the steady drumbeat of GOP opposition to the health-care law. And now, in spite of the facts, many Americans think the law is unconstitutional. Blame the Obama administration's "abject failure" to explain its own law. "Of course the public thinks the law is unconstitutional. They never heard a single word defending it."

4. The fight is making everyone forget why we need reform
The law's opponents make it sound like defeating the unpopular individual mandate solves all our problems, says Rick Newman at U.S. News & World Report. But the mandate, by expanding "the pool of people covered by health insurance," makes popular pieces of "ObamaCare" possible. If it goes, so do subsidies for those who can't afford insurance, and the ban on denying coverage over pre-existing conditions. Then we're right back where we started, with a sixth of the population uninsured, and people dying or being financially ruined because they have no health insurance. But no one is talking about such systemic problems. We're all too busy harping on the "ObamaCare" bogeyman.