How Can Obama Appear on Letterman after Boycotting Imus?

Two years ago, after radio-show host Don Imus called the young ladies on the Rutgers basketball team "ho's," presidential candidate Barack Obama announced he would not appear again on Imus' show.

But he didn't stop there. Shortly after Imus apologized, Senator Obama also called for him to be fired. ABC's Jake Tapper reported that of the major presidential candidates, "Obama is the first one to say Imus should lose his job..."

Obama's unforgiving stance, while understandable, was in striking contrast with his offers of healing, reconciliation, and dialogue to Iran and North Korea.

Obama said that Imus "didn't just cross the line. He fed into some of the worst stereotypes that my two young daughters are having to deal with today in America...It was a degrading comment. It's one that I'm not interested in supporting [by appearing on Imus' show]"

David Letterman's joke about Sarah Palin's 14-year-old daughter getting pregnant at a Yankees game, and characterization of Palin as "slutty," were remarkably similar to Imus' offense, the main difference being that Imus expressed sincere regret. Letterman's peculiar "apology" was that he had really intended to demean Palin's 18-year-old daughter, not the 14-year-old; and he never apologized for calling Palin a slut.

President Obama has reversed his zero-tolerance stance against the degrading of girls and women, and will be Letterman's guest for a full hour on Monday, the first sitting president to appear on the show. If Letterman had sexually demeaned one of President Obama's daughters and called the First Lady "slutty," would Obama be appearing on the show? Would Letterman even still have a show?

Update: Irony Curtain's take: