When a recent Pew poll showed that 18 percent of Americans believe that President Barack Obama is Muslim, many observers concluded it was due to a combination of generalized anti-Obama sentiment and a conservative whisper campaign to smear the Democratic president. If so many Americans can believe something this absurd and obviously false, what won't they believe? The Onion tests the boundaries of anti-Obama rumor mongering with a satirical news story: Poll: 1 in 5 American Believe Obama is a Cactus

WASHINGTON—According to a poll released Tuesday, nearly 20 percent of U.S. citizens now believe Barack Obama is a cactus, the most Americans to identify the president as a water- retaining desert plant since he took office.

... According to the poll, Obama has lost favor among many voters who supported his candidacy in 2008 but have since come to doubt he is a mammal. While these Americans concede Obama may not specifically be a cactus, most believe he is a plant of some kind, with 18 percent saying the president is a ficus, 37 percent believing him to be a grain such as wheat or millet, and 12 percent convinced he is an old-growth forest in Northern California.

The Onion's (false and satirical) story blames "cable news outlets that suggest the president has prickly spines he uses to protect himself from thirsty animals" as well as Republican opponents. "Some Beltway observers have accused Republicans of tacitly encouraging the cactus rumor, pointing out that if millions of voters believe Obama produces buds through spirally arranged areoles situated along his stem, the GOP has a much better chance of retaking Congress in November."

Obviously, Obama is not a cactus. But he is just as clearly not Muslim. The Onion seems to be suggesting that if Americans are willing to believe something as crazy as the Muslim-Obama rumors, and if some conservatives are crass enough to push those rumors, what's stopping critics from going a step further and accusing Obama of being "a large succulent plant composed of specialized cells designed for water retention in arid climates"?