It was so much easier when Johnny was around.
Mr. Carson's departure from late-night television a decade ago prompted one of the biggest battles in the franchise's history, as Jay Leno and David Letterman fought over his seat on NBC's "The Tonight Show."
When Carson was at the helm, the other networks were unsuccessful in offering anything that could compete, with the exception of ABC. It tried something different in 1979 - a news program that eventually became "Nightline."
More than 20 years later, there are two dominant late-night comedy shows, cable channels galore. Network programmers are no longer satisfied pitting news against entertainment at bedtime.
The news last week that Disney-owned ABC had offered the hour occupied by "Nightline" and "Politically Incorrect with Bill Maher" to Mr. Letterman indicates that the latest late-night battle is driven not by a coveted seat, but a coveted demographic - and the bottom line.
"Late night is hip, sexy, and edgy, and people want a piece of that - ABC especially, right now," says Matthew Felling, media director at the Center for Media and Public Affairs in Washington.
"Nightline" has been fending off Mr. Letterman for the last decade, ever since the comedian found out he was not the heir to the "Tonight Show." Most major networks, including ABC, tried to woo him then.
But the award-winning news program, with its respected anchor, Ted Koppel, has remained alive and competitive. It is typically No. 2 in the late-night - trailing Mr. Leno's "Tonight Show." In February, it had about the same number of viewers as Mr. Letterman - 4 million - but both trailed Leno, who attracted more than 6 million viewers.
In the current environment, though, raw numbers aren't necessarily what executives are interested in: It's who's watching. They covet more the young, Old Navy crowd than those whose first stop everyday is a newspaper.
" 'Nightline' has a sizeable and valuable audience that is more than viable for most marketers. But in general it will not bring in more revenue than higher-rated rivals, particularly 'The Tonight Show,' " says John Rash, director of broadcast negotiations at Campbell-Mithun, an advertising agency in Minneapolis.
But beyond the late-night dollars, traditional networks are facing a larger challenge in a market that has changed dramatically - thanks to corporate ownership and drops in ad revenue. Signs of that pressure are evident in how quickly new programs are pulled if they don't perform well, and moves like NBC's recent decision to lift a 50-year ban on hard-liquor ads.
The tension between news and entertainment has also increased as a result. Decades ago when there were only three major networks, popular entertainment shows could help pay the way for their news counterparts. But today, news has to bring its own money to the table.
Many people have come to Mr. Koppel's defense, but even he has said he understands the corporate pressure his owners face. In an Opinion article in The New York Times this week, Koppel made his first public comments about the situation. Despite his concession to the bottom line, he defended "Nightline's" ability to get top ratings in times of crises, and pointed out that it has earned more than half-a-billion dollars for its owners over the years.
His main grievance, though, was the suggestion that the program is no longer relevant, a charge made in the press anonymously by an executive close to the negotiations. "I would argue that in these times ... when, in short, the regular and thoughtful analysis of national and foreign policy is more essential than ever - it is, at best, inappropriate, and, at worst, malicious to describe what my colleagues and I are doing as lacking relevance," Koppel wrote.
Despite its devout following - ABC has received thousands of supportive e-mails in recent days - "Nightline"does exist in a news environment significantly different than the one in which it began. The Internet and 24-hour cable networks put news at people's fingertips all day long. That leaves many wanting to relax, rather than be informed, before bed.
"At that time, I'm kind of settling in for the night, and I want to watch something entertaining, not thought-provoking. Just something I can drift off to sleep to,"says Michelle Widows, a clinical phycologist at the University of Florida in GainsvilleCK
In fact, that's something broadcasters have known for a long time. They have tried to entice viewers over the years with late-night hosts such as Arsenio Hall, Magic Johnson, and Chevy Chase.
Those who do last - Letterman, Leno, and those whose shows follow theirs, like Conan O'Brien - are coveted by networks who know how difficult it is to build an audience from scratch. When Mr. O'Brien's contract was up for renewal with NBC recently, he was unsuccessfully courted by Fox for a late-night show.
Even some of those who are faithful to the hosts, however, see the need for "Nightline."
"I'm a Letterman fan. I watch three to four nights a week. But 'Nightline,' I think, is still very valuable," says Gregg Wrenn, a writer for teevee.org, who is in his late 20s. "It's not that I'm saying I don't want news at 11:30 at night. I just prefer Letterman," he says, adding. "In terms of Sept. 11 and all that, it seems like this would be a stupid time to cancel 'Nightline.'"
Other Letterman followers are more adamant about no news. "I'm just not in the mood for news that late. Given the choice between news and sleep, I'd probably choose sleep," says Owen Ellickson, another 20-something who is a writer's assistant on "King of Queens," a CBS sitcom.
Among the reasons that Letterman was believed to be interested in leaving that network for ABC was to have better lead-in audiences from local news than he does now.
"It seems like Dave's unhappy wherever he goes. That's part of what makes him great," says Mr. Wrenn. "People love the cranky Dave."
Some media critics argue that if Letterman were to move to ABC - which may be increasingly unlikely, given that he reportedly does not want to be the reason for "Nightline's" demise - CBS would likely tap some other comedian for a talk show, and the audience would have to be split three ways.
That may happen even if Letterman doesn't make the switch, with ABC suggesting it will replace its current late-night lineup eventually anyway, possibly putting "Nightline" somewhere else in prime-time.
The bid to Letterman, says Mr. Rash of Campbell-Mithun, "is generated almost exclusively by ABC's desire to reinvigorate their entire network, and fundamentally make more money."