In Egypt, 43 percent of people think Israel was behind the 9/11 attacks in America, a poll by WorldPublicOpinion.org found last year.

In the United States, six percent of Americans say the moon landing of 40 years ago was staged, according to Gallup.

And in Alaska, the former governor, a woman who was nearly a heartbeat away from the presidency, now tells followers that “Obama death panels” could decide if her parents and her baby, Trig, who has Down Syndrome, will live or die.

The United States, like most countries, has long had a lunatic fringe who channel in the flotsam of delusion, half-facts and conspiracy theories. But now, with the light-speed and reach of the Web, “entire virtual crank communities,” as the conservative writer David Frum called them, have sprung up. They are fed, in the case of Sarah Palin, by people who should know better.

For a democracy, which depends on an informed citizenry to balance a permanent lobbying class, this is poison. And it’s one reason why town hall forums on health care, which should be sharp debates about something that affects all of us, have turned into town mauls.

The lies and shouts have had the effect that all crank speech has on free speech — stifling any real exchange. In my state, Representative Brian Baird, a veteran of more than 300 town hall meetings during his 11 years as a Democratic congressman from southwest Washington, has decided not to hold any such forums this recess after receiving death threats.

But is it any wonder that some are moved to violent threats, given the level of misinformation being injected into the system? If you really believed that Obama was going to kill your baby and euthanize your parents, well — why not act in self defense?

Here’s what Palin said on her Facebook page Friday, in her first online comments since quitting as Alaska governor.

“The America I know and love is not one in which my parents or my baby with Down Syndrome will have to stand in front of Obama’s ‘death panel’ so his bureaucrats can decide, based on a subjective judgment of their ‘level of productivity in society’ whether they are worthy of health care.”

This is pure fantasy, fact-free almost in its entirety. The nonpartisan group FactCheck.org said there was no basis for such a claim in any of the health care bills under consideration in Congress. One House bill would pay for counseling for terminally ill patients — something anyone who has lost an elderly loved one of late, as I have, will find essential.

Palin was given some cover Sunday by the former House Speaker Newt Gingrich, a master of slipping innuendo into his arguments. Defending the “death panel” post on ABC’s “This Week,” Gingrich said, “you’re asking us to trust the government.” By such reasoning, American foreign policy is not worth its word, the currency is worthless, and the moon landing was indeed a fake.

The last time Gingrich went so far was when he called Justice Sonia Sotomayor a racist. He retracted it then. We’ll see what he does now. As for Palin, she should follow her own advice to the media of a few weeks ago — lay off the kids and “quit makin’ things up.”