WASHINGTON – Sometimes you just want to shake your head and wonder what’s in the water.

That could be the intro to musings about lots of things, from parents who force their oversexualized 5-year-old daughters into beauty contests to Gov. Mark Sanford.

But today I’m thinking about those folks who help their kids with the homework, make a casserole for the lonely old lady across the street, run their daily two miles, phone a parent in another state or a kid in college, trim the grass that keeps growing onto the sidewalk, buy a just-because card for their sweetie, think deeply about how to cut household expenses … and still have time to scream at members of Congress for not making President Obama’s citizenship Priority One.

For those of you who actually have a life (see above) and may not have heard the echoes from the whack-a-doo chorus, here’s the short version: A rumor from the 2008 campaign persists: Obama was born in Kenya, not Hawaii, and therefore is ineligible to serve as president because the Constitution requires presidents to be natural-born citizens.

A copy of the Hawaiian birth certificate doesn’t convince the “birthers,” as they have come to be known. Statements by the director of the state’s health department that she has seen and verified the birth certificate don’t quiet them. Court cases to the contrary don’t resolve it for them. A unanimous vote in the House last week congratulating Hawaii on 50 years of statehood and containing the sentence that Obama was born there is irrelevant to them.

Birthers, aided by pundits such as Lou Dobbs, simply will not believe any document, statement or fact. They are convinced that Obama is an African by birth and thus constitutionally barred from the Oval Office. They are sure that any evidence to the contrary is concocted.

Conspiracy theorists will always be with us, and sometimes there are reasonable assumptions – even facts – that support the theory.

But not in this case.

Yet the birthers remain nearly hysterical in their belief. There’s an astounding video clip on YouTube of a town hall meeting conducted by a Delaware Republican congressman in which a birther literally screamed at Rep. Mike Castle – to cheers and applause from the crowd – that Congress was ignoring that “Obama is not an American citizen. He is a citizen of Kenya.”

Before demanding the audience recite the Pledge of Allegiance, she screeches: “I don’t want this flag to change! I want this country back!”

Alas, she is not unique.

That’s bad for Republicans. The birthers don’t really expect Democrats in Congress to do anything about what they think is a fraud perpetrated on the country. But they are demanding that the GOP Do Something.

House members left Washington this weekend for a five-week vacation. Typically, many have town hall meetings during the August break. It’s a good opportunity for constituents to ask questions, air their concerns and take the temperature of their representative.

There’s plenty to talk about – health insurance, energy policy, the ragged economy.

But you’d understand if some Republicans are reluctant to create an environment that allows birthers to hijack the event. At public meetings the birthers force lawmakers either to agree with their accusations or to say the issue has been resolved: that Obama is a U.S. citizen.

A member of Congress who takes the first path looks like a lunatic and certainly would be legitimately challenged for doing nothing if he or she honestly believes the occupant of the White House is there fraudulently. The path of sanity inevitably leads to accusations of being an Obama apologist.

A sidestepping “that’s for others to decide” implies that they are open to the possibility that the Hawaiian birth certificate is a fake.

Hey – maybe that’s all part of a plot. Maybe the birthers are really members of MoveOn.org. Maybe the game is to further divide the Republican base. Maybe what they really want to do during the summer break is create a noisy diversion so constituent feedback on the climate and health care bills is drowned out.

Now that’s a conspiracy theory worth a beer or two.