Rep. Marsha Blackburn (R-Tenn.) laced into President Barack Obama in an open letter today, blasting him and his campaign for producing an advertisement that uses a double entendre-laden theme to encourage first-time voting.

The ad was a testimonial from actress Lena Dunham of HBO’s “Girls” fame. In the spot, she quite obviously compares losing one’s virginity to voting for the first time.

“What could you possibly have been thinking?” Blackburn writes in her letter. “The ad you have launched featuring a young actress equating voting for you to a sexual act is offensive to me, to millions of women and to the stature of the office you hold. As a father of two beautiful girls, how could you possibly have allowed this to be aired?”

Blackburn also employed language rarely heard since the 1998 Monica Lewinsky scandal during the Clinton administration: “It is beneath the dignity of the office you hold.”

It is not clear if the ad was intended for Web or television use. The Obama campaign did not respond immediately to a request to clarify buy information or for a comment on the matter.

The one-minute spot was posted on the Obama campaign’s YouTube page, but it did not include the words, “I’m Barack Obama and I approved this message.”

Daniel Newhauser contributed to this report.