One day we imagine people will look back on the last eight years and maybe think it strange how the country became dependent on its late-night comedians to address the obvious. In the meantime, CBS execs are apparently pissed off at David Letterman for using internal CBS feed of John McCain prepping with Katie Couric during his rant about McCain canceling his appearance on the show the other night.

Asked if CBS officials had a problem with Letterman using the internal news feed, a spokeswoman for "The Evening News" refused to address the issue.

But several CBS News executives — who asked not to be identified — said that the stunt did not go down well within the news division.

"If we had done something like that to him, someone around here would end up getting fired," one said.

News officials found out Letterman was using the internal feed shortly after it showed up on an internal CBS feed carrying the "Late Show" taping.

"They were pretty aggravated," a CBS News source told The Post.

"But they were not about to start a fight with Letterman," the source said. "We're in the middle of a heavy, heavy news cycle and Letterman is Letterman.