What's President Obama's cousin doing on the Kansas ballot?

Kansas Sen. Pat Roberts (R) faces an unusual challenger in Tuesday's GOP primary: a distant cousin of President Obama's. Here's how they're related.

If Milton Wolf of Kansas has his way Tuesday, he will be best known for unseating a three-term senator, Pat Roberts – and he’ll be the new hero of the tea party.

Thus far this year in GOP primaries, the movement is batting .000 in its efforts to unseat an incumbent Republican senator. After failing, barely, to take out Sen. Thad Cochran (R) of Mississippi in June, national tea party groups now see Kansas as their best shot at victory. But it’s still a longshot. In the latest nonpartisan poll of the race, taken in July, Dr. Wolf trailed Senator Roberts by 20 points.

Yes, we know: Soon-to-be-ex-Rep. Eric Cantor, the former Republican leader in the House, lost his primary to a tea party unknown in a June shocker. The same could happen to Roberts. But Senate primaries are different from House primaries. It’s harder to sneak up on a senator, or at least one who has had plenty of fair warning, as Roberts has. And Wolf is a flawed challenger. More on that in a moment.

One of Wolf’s most memorable biographical points is that he’s a blood relative of President Obama’s. Really. Wolf’s mother was a cousin of Obama’s American grandmother, which makes Obama and Wolf second cousins once removed. For people interested in genealogy, The Washington Post has drawn a family tree to show the exact connection.

But there’s more to the story. The Post links to a 2009 interview with Wolf’s mother, Anna McCurry Wolf, conducted as part of an oral history project focused on Obama’s Kansas roots.

“Perhaps the most charming part of the interview with Anna McCurry is her obvious excitement about being related to the president,” writes Philip Bump in the Post.

“She'd heard that the family was related to a black man from Chicago, and then saw his 2004 convention speech. When she heard him refer to a white grandmother from Kansas at some point, she told her second husband, Gene Colle, ‘that kid has to have the same DNA I have. That has to be Stanley Ann's son.’ It was. She traveled to D.C. with a group from Kansas and met Obama, who gave her an autographed copy of his book.”

There’s no word on what Obama thinks of his tea party cousin’s effort to come to Washington and make the president’s life more difficult. But, as we already said, chances are Wolf won’t get here.

And here’s why: Back in February, The Topeka Capital-Journal published a story about gruesome X-rays of deceased patients that the radiologist had posted on Facebook - including inappropriate comments.

That revelation dealt a major blow to Wolf’s campaign, which failed to attract an endorsement from the wealthy Club for Growth. The fact that he’s still getting media attention is a testament to Roberts’s vulnerability.

One outside group that is supporting Wolf and has invested in ads on his behalf is the Senate Conservatives Fund. A poll by the group released July 31 shows Wolf’s deficit down to 9 points.

But we’ll believe that Wolf can actually win when we see it.