The resignation of White House “green-jobs czar” Van Jones because he signed a “truther” petition calling for an investigation of US government involvement in the attacks on 9/11 reminds us of the prevalence of 9/11 conspiracy theories. Large numbers of Americans believe them. In doing so, wittingly or unwittingly, they do a great disservice to the millions of dedicated men and women who serve them.

Opinion polling organizations have conducted numerous surveys about 9/11 conspiracy theories over the years with varying results. As with all polls much depends on how they ask the question. Still, as many as one-third of Americans believe that the US government either assisted in the 9/11 attacks or took no action to stop them.

It's easy to write off people that believe 9/11 conspiracy theories as the lunatic fringe when we see flakey celebrities like Rosie O’Donnell and Charlie Sheen spouting off about them on TV. Anti-war liberals and radical activists like Jones have an affinity for conspiracy theories. Nevertheless, they are not the exclusive province of the left. People on the right-wing fringe love them as well.

But it's not just the lunatic fringe that believe them, unless you believe that a third of Americans are lunatics. Most believers are honest, hard-working, and loyal Americans. Professionals that study people who believe in conspiracy theories have offered numerous explanations for their susceptibility to them. They range from guilt transference by people that have difficulty coming to grips with how vulnerable we are to our enemies to honest but uninformed people accepting the “proof” of those who maliciously stoke the flames of conspiracy to advance their personal agendas.

Whatever the explanation, conspiracy theories are an established part of American popular culture. “President Franklin Roosevelt knew about Pearl Harbor and did nothing to prevent it.” “Lee Harvey Oswald didn’t act alone in the assassination of John F. Kennedy, and the US government is covering up the truth.” “Hundreds of American POWs and MIAs from the Vietnam War remained in captivity after the US withdrew from Vietnam and were abandoned by the US government.” And now, “the US government was complicit in the attacks on 9/11 so it could go to war in the Middle East.”

POW/MIA conspiracy theories have a special relevance for me. From 1992 to 1994 I served as the Acting Deputy Assistant Secretary of Defense for POW/MIA affairs. I was one of those government officials accused of covering up the “truth.” An unscrupulous former US Senator even wrote a letter to Attorney General Janet Reno accusing me of high crimes and misdemeanors. The Department of Justice dismissed the allegations as unfounded, but as is almost always the case, the conspiracy junkies just added that to the pile of evidence that proved there was a conspiracy.

Like 9/11 conspiracy theories, no matter how many documents the US government declassified about POWs and MIAs in Vietnam or how many times the same conspiracy theory was debunked, someone would come along and write another book or article about all the “evidence” that proved them.

My POW/MIA experience taught me that the US government, unfortunately, does play a role in helping create conspiracy theories. It badly neglected and mismanaged the POW/MIA issue immediately after the war during President Jimmy Carter’s administration. We had no access to the war zone after 1975 and the Vietnamese government was non-cooperative, but Carter could have given the issue a much higher priority and deprived the seeds of conspiracy time to germinate.

Similarly, Franklin Roosevelt was disingenuous before Pearl Harbor about keeping America out of World War II. The US government plotted to assassinate Fidel Castro during the Kennedy administration, had contacts with the Mafia, and then tried to cover them up. George W. Bush’s misadventures with weapons of mass destruction in Iraq raised doubts about him and his administration in many people’s minds.

These and other chains of events--from Watergate to President Bill Clinton’s attempt to cover-up the Lewinsky scandal--only contribute to American’s skepticism of their government. Whether art imitates life or life imitates art, people who write novels and make movies about real and fictional events add fuel to the fire, routinely portraying the US government as one big conspiracy factory. When someone comes along with a plausible sounding accusation that the government is covering up something big, many people find such accusations easy to believe.

Nevertheless, it's important that we distinguish between power-hungry and often corrupt officials using government for their own selfish and political purposes and the millions of honest, dedicated men and women who serve and protect us.

The Achilles’ Heel of grand conspiracy theories is that they require hundreds if not thousands of these people to carry them out and keep them secret. If the US government has demonstrated anything during its long history, it’s that it can’t keep those kinds of secrets. To believe that hundreds of US government and military personnel knew about US complicity in an attack that killed 3,000 Americans on 9/11 and none of them would come forward or leak the news to the press is ludicrous.