A new USA Today/Gallup poll offers some sobering numbers about President Obama's signature domestic policy achievement. The Affordable Care Act is broadly unpopular among registered voters, the poll finds, with half calling its passage a "bad thing" and 42 percent a "good thing." In 12 crucial swing states, the numbers are worse: 53 percent "bad" versus 38 percent "good." Also, 72 percent of all polled adults believe the ACA's individual mandate is unconstitutional, including 56 percent of Democrats. Furthermore, half of registered voters want the law repealed if a Republican beats Obama in the fall, versus 44 percent who don't. Why are Americans so down on health-care reform? Here, three theories:

1. Americans hate the individual mandate
"The more Americans know about ObamaCare, the less they like it," says Investor's Business Daily in an editorial. Blame the individual mandate, which requires Americans to have health insurance. Voters are finally realizing that "ObamaCare will, for the first time ever, force Americans to buy a government-approved product merely because they have a pulse." Plenty of us "dirty hippies" warned Democrats that people wouldn't like being forced to "buy health insurance from private, for-profit, and hated insurance corporations," says Martin Longman at Booman Tribune. If there were a public health insurance option, ACA would be much more popular.

2. The law isn't helping many people... yet
A relatively small number of the ACA's provisions have already gone into effect. (For instance, young adults can now stay on their parents' insurance until age 26.) But the biggest parts don't kick in until 2014. That means Americans "are not seeing much in the way of positives," Gail Wilensky, a policy adviser for President George W. Bush and critic of the law, tells USA Today. Just 11 percent of registered swing state voters said the law has helped their families, versus 15 percent who said it's hurt. A whopping 72 percent said the law has had no effect.

3. Obama has failed to sell the law
While critics have been swamping the airwaves with a "torrent" of opposition and misinformation, ACA supporters are "relying on the president to do the selling, and he's moved on to other things," Brandeis University professor Stuart Altman tells USA Today. The result is a "drumbeat of negative comments and almost no positive" force counteracting it. Yes, "the president and the Democrats need to go on offense," says Booman's Longman. "I suggest a massive ad campaign that uses real beneficiaries of the health care bill."