New York ? ABC’s efforts to persuade David Letterman to switch networks could set up a classic struggle over whether entertainment or journalism is more important at a financially struggling company.

The network has made a pitch for the talk-show host, whose contract with CBS expires this summer. CBS is also trying to keep Letterman, according to sources close to the negotiations who spoke on condition of anonymity. Letterman moved to CBS from NBC in 1993.

If the Walt Disney Co.-owned ABC is successful, it would oust “Nightline” and host Ted Koppel from the 10:35 p.m. time slot that show has held for more than two decades.

The news hit like a bomb at ABC News, where “Nightline” has been considered a flagship.

Neither Koppel, who was returning from a vacation Friday, nor ABC News President David Westin knew about the Letterman talks until late Thursday, according to a network executive.

Koppel, who did not return a call seeking comment, gathered his staff for a meeting about his show’s future on Friday.

“If Disney replaces ‘Nightline’ with more entertainment programming, it will be strong evidence of the threat to journalism represented by TV networks that have been taken over by entertainment conglomerates,” said Peter Hart, an analyst for the liberal advocacy group Fairness & Accuracy in Reporting.

“Nightline” began as a regular show in 1980, an outgrowth of the network’s coverage of the Iranian hostage crisis. But ABC executives are reportedly concerned that its ratings are slipping and, like many news shows, attracts an older audience that is less desirable to advertisers.

An angry Westin argued in a staff meeting Friday that “Nightline” is a profitable show, said a source who requested anonymity. And although its ratings are going down, the decline is not as fast as it is for general ABC fare earlier in the evening.

ABC executives are reportedly trying to find other places for “Nightline,” perhaps as a less regular series on the prime-time schedule.

ABC and CBS representatives declined comment Friday on the Letterman talks.

Rob Burnett, CEO of Letterman’s production company, Worldwide Pants, said: “We are continuing negotiations with the CBS television network. It would be inappropriate at this time to discuss any inquiries that we have received from other networks.”

Letterman has for several years been No. 2 in the ratings behind NBC’s Jay Leno in the late-night comic wars. He has long been unhappy that CBS’ older prime-time audience and the weak local news programs on CBS affiliates don’t provide him with a stronger lead-in.

He also is said to be unhappy with the pace of negotiations with CBS, according to The New York Times, which reported on the talks Friday.

A move to ABC would come with some risk. Although ABC has slightly stronger prime-time ratings than CBS among viewers age 18-to-49, that advantage has shrunk considerably this year as ABC as a whole struggles.

There’s some question about whether CBS misread its contractual ability to have exclusive negotiations with Letterman. There is also a dispute over whether ABC still has the ability to keep talking to Letterman.