You see, Sen. Coburn is in trouble with the Senate Ethics committee for delivering babies for free.

Coburn has come under new pressure from the Ethics panel for delivering babies at the Muskogee Regional Medical Center, which changed from a public to a private institution in April last year after it was acquired by Capella Healthcare.

Because of potential conflicts of interest, Senate rules prohibit members from receiving compensation for practicing a profession that involves a fiduciary relationship. Coburn’s work as an obstetrician has been a subject of interest for ethics panels in the Senate and the House when he was a representative.

Sources said the fact that Muskogee is now a private hospital has renewed the ethics panel’s interest in Coburn’s work.

In May, Coburn received a strongly worded “final determination” memo threatening him with a Senate censure if he did not stop delivering babies for free. The letter prompted several heated meetings between Coburn and the Ethics Committee in June over the matter, according to two knowledgeable Senate sources.

“Just as parents don't choose him hoping to sway his vote, parents don't choose to receive his services at a particular hospital because Dr. Coburn has somehow endorsed that hospital because he is a senator,” Hart said in a statement e-mailed to The Hill. “The committee has shown us zero empirical evidence to back up its flimsy claim.

“Has Sen. Leahy provided an improper endorsement to Warner Brothers for appearing in Batman?” Hart asked. “Will millions of Americans now see Batman not because it features stars like Christian Bale or the late Heath Ledger, but because Patrick Leahy, a distinguished United States senator, has offered his illustrious endorsement to this motion picture?

“If Sen. Coburn can only deliver babies for free at a public hospital, shouldn't Sen. Leahy only be allowed to donate his notable thespian skills to a public entity like PBS?”