MARK KIRK MAY HAVE A PROBLEM…. Usually, when we talk about political candidates with a “problem,” we’re talking about issues that may cause trouble for their campaign. When I refer to Rep. Mark Kirk (R) in Illinois having a “problem,” I mean there might just be something wrong with him.

Kirk, the Republicans’ U.S. Senate nominee, has described himself to voters as “a former nursery school teacher.” His campaign has said Kirk worked “as a nursery school teacher.” In reality, Mark Kirk wasn’t a nursery school teacher.

A leader of the church in upstate New York where Representative Mark S. Kirk of Illinois claims he worked as a nursery school teacher said on Friday that he had overstated his role there.

The leader, Sally Grubb, a member of the administrative council at Forest Home Chapel, a Methodist church in Ithaca, N.Y., said Mr. Kirk had a limited role while working part-time in a work-study program while he was a student at Cornell University nearly three decades ago.

“He was never, ever considered a teacher,” Ms. Grubb said in a telephone interview after researching the history of Mr. Kirk’s association with the nursery school. “He was just an additional pair of hands to help a primary teaching person.”

Apparently, the school had a play group that met in the church basement. Kirk helped out, but he “did not have major responsibilities at the play group, like creating lesson plans, and he was assistant who played with the children.”

As a substantive matter, what Kirk did as a college student in 1981 seems to have no relevance today. The point, though, is that Kirk keeps making specific claims about his background — using his experiences to impress voters — that fall apart under scrutiny. He’s saying what he did as a college student in 1981 is entirely relevant — he referenced his nursery school background with the Illinois Education Association, in the hopes of getting an endorsement — but Kirk’s version of events just isn’t true.

More importantly, it seems Kirk can’t seem to help himself when it comes to telling tall tales. When describing his military service, Kirk has made at least 10 specific false claims. When describing his views on foreign policy, he’s made several more false claims. Now we learn that Kirk’s claims about having been “a nursery school teacher” aren’t true, either.

How voters are supposed to find Mark Kirk trustworthy going forward remains a mystery.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.