With Sen. Tom Coburn (R) retiring at the end of the year, well ahead of the scheduled end of his term, there will be a Senate special election in Oklahoma in 2014. Given the fact that the Sooner State is one of the “reddest” in the nation, it’s very likely the seat will remain in Republican hands. The question is which Republican.

Rep. Tom Cole (R) and state Attorney General Scott Pruitt (R) quickly withdrew from consideration, but Rep. James Lankford (R) launched his campaign yesterday, vowing in his announcement speech to “continue Dr. Coburn’s conservative legacy.”

In theory, the right-wing congressman, elected in the 2010 GOP wave, would appear to be exactly the kind of candidate far-right activists would hope for. Conservative groups don’t quite see it that way.

[T]he Senate Conservatives Fund, a key pressure group, took the stark step Monday morning of saying – even before Mr. Lankford’s official announcement – that he will not be getting their support. “We won’t support Congressman Lankford’s bid for the Senate because of his past votes to increase the debt limit, raise taxes and fund Obamacare,” said Matt Hoskins, the group’s executive director. […] The Madison Project, another group that directs attention and money to the campaigns of anti-Washington candidates, said Mr. Lankford is the wrong candidate for the party. In a blog post, the group said Mr. Lankford isn’t a “purely liberal Republican,” but said he is “a quintessential status quo Republican.”

This isn’t a intra-party dynamic in which the Republican base rejects an electable, mainstream candidate, boosting Democratic chances of picking up a competitive seat.

Rather, this is the latest evidence that for GOP-affiliated organizations hoping to influence elections, being conservative is no longer conservative enough.

To hear the Senate Conservatives Fund and its allies tell it, Lankford is some kind of RINO. I poked around the ThinkProgress archive this morning to get a sense of some of the congressman’s greatest hits and found a few gems:

* Lankford believes sexual orientation is a “ choice ,” so employment discrimination against gay Americans should be legal

* He believes climate change is a “ myth ,” pushed by those seeking to “control” people.

* He blamed “ welfare moms ” for gun violence.

* He wants the United States to defund and abandon the United Nations

The Senate Conservatives Fund and its allies think this guy just isn’t conservative enough. Perhaps some folks are just tough to please.