The NCAA Tournament is among the most expensive buys in all of sports. CBS has the broadcast rights to 63 men's basketball games in 10 days spanning the tournament's 2½-week run at the cost of approximately $32 million per day.

But the possibility of war against Iraq threatens to interrupt the first year of the network's 11-year, $6 billion investment, which includes exclusive TV, radio, Internet, home video and marketing rights, prompting CBS officials to prepare contingency plans should the conflict begin during the tournament.

"We're on the phone literally three or four times a day exploring, seeing where we are as a country," CBS president Les Moonves said last week. "Obviously when you are dealing with a network you have a great deal of responsibility."

The possibility of war later in the week seemed to become more possible Monday when, in a break with longtime allies, President Bush jettisoned diplomacy and demanded that Saddam Hussein surrender power or face a military attack. The United Nations "Security Council has not lived up to its responsibilities so we will rise to ours,'' Bush said, hours after a decision to withdraw a United Nations resolution that appeared headed for rejection.

Should a war begin later this week, CBS likely would show wall-to-wall coverage of the first few days of the conflict to fulfill its affiliates' FCC responsibility to best serve the public's interest. The games then could move to other Viacom-owned networks, including TNN and Nickelodeon.

Although a deal with ESPN was not completed as of Tuesday evening, the network would be able to broadcast first-round games on Thursday and Friday. The network also is in the process of clearing room for men's basketball for second round programming, although ESPN will still cover the NCAA women's basketball tournament, which begins on Saturday.

If ESPN does get the early-round games, one game will either be on ESPN or ESPN2. The network could then provide regionalized coverage.

ESPN spokesman Josh Krulewitz confirmed that the network has had talks with CBS. "The sole reason was to potentially serve fans and the NCAA under what are very unique and difficult circumstances," he said. "There are a number of complications including but not limited to our other programming commitments, including broadcasting all 63 games in the NCAA women's basketball tournament."

Said CBS Sports president Sean McManus, "The decision we'll make at the time will factor in our journalistic responsibility to the war coverage as well as to the basketball fans, but we've got to make that call at the line of scrimmage."

CBS canceled its broadcast of a college basketball game and moved its coverage of the Bob Hope Classic back an hour when the Columbia space shuttle exploded Feb. 1.

How much CBS would lose if games were switched to its cable affiliates depends on ratings, since the network guarantees a minimum viewership to its advertisers. CBS is broadcast in approximately 107 million U.S. households, while TNN is in 85.8 million homes, ESPN is in 86.7 million homes and ESPN2 is in 84.5 million homes. Another Viacom option, TV Land, only reaches 78.4 million households.

"When you are talking about a war in Iraq with 300,000 American soldiers over there, there's no way anyone argues that war should not be covered, or delayed, or deferred, so that CBS can get our NCAA basketball games on the air," said former CBS Sports president Neal Pilson, who dealt with cutaways from the network's broadcasts of the AFC and NFC title games to coverage of the first Persian Gulf War 12 years ago.

The first four days of the NCAAs are by far the main network's largest blocks of programming, though advertising revenue in the early rounds isn't as crucial as it is deeper into the tournament. Sixteen games are scheduled per day on March 20 and 21 and another eight per day on March 22 and 23.

"You can make the case that once we make it to the regional semifinals (March 27 and 28) that people will find the games," McManus said. "But if the first couple rounds aren't great, we'll obviously have to make it up to our advertisers."

In its contract with the NCAA, CBS has the right to move its broadcast of the men's tournament to its cable partners, but there is no structure in place that reduces the rights fees paid or the ratings promises for advertisers, McManus said.

The only time the NCAA financially accommodated CBS was believed to be during the first year of the network's tournament coverage in 1982, when CBS inadvertently left out $1 million worth of advertising. After some negotiation, the NCAA provided extra space between games to allow CBS to fulfill its requirements to its advertisers, Pilson said.

If CBS had to switch channels, it could put national games on several of its cable stations, but it won't be able to do its popular split-screen look-in at multiple games or be able to provide regional coverage. Potentially frustrated college basketball fans might consider springing for DirecTV's NCAA Tournament package, which offers 37 early-round, out-of-market games for $49. Those with broadband connections, also have the option of paying $16.95 for Yahoo's Platinum service, which will feature live streaming video of 56 games through the Sweet Sixteen.

"We have a system in place that is very complex," McManus said. "But it's hard to duplicate what you've worked to perfect over the last 20 years."

CBS won't be the only one reeling from war coverage, as all the major networks likely will drop commercials.

"If NBC loses its primetime programming of 'Friends' and 'ER,' where commercials can cost $500,000 or more, one night could mean a quick $12 million to $15 million loss," Pilson said.

Darren Rovell, who covers sports business for ESPN.com, can be reached at darren.rovell@espn3.com. The Associated Press contributed to this report.