Tennessee Scandal: Non-Citizen Legislators?

The Tennessee State Constitution requires that its legislators be, among other things, U.S. citizens.

Now, questions are being raised about whether four Republican legislators--Reps. Eric Swafford, Stacey Campfield, Glen Casada and Frank Nicely--actually meet the citizenship requirement.

Even as the controversy swirls around them, all four remain silent on the issue. So far, none of the four has offered any proof at all that he really is a U.S. citizen. It shouldn't be that difficult...unless, that is, no such proof exists.

So are there four people serving in the Tennessee legislature who are constitutionally prohibited from serving? I don't want to jump to conclusions, but I certainly haven't seen any evidence of their citizenship...and their failure to produce any is damning indeed. And really, now: does Casada sound like an American name?

All I know is this: if I were a Tennessee citizen, I would file a lawsuit to force them to prove their qualifications. After all, the people have a right to know.