To cover this summer’s Olympic Games, NBC News will deploy a journalistic force of some 450 people, including 25 reporters and its lead anchorman, Brian Williams. The network has been featuring Olympic updates on the Williams-anchored “Nightly News” and softer stories every morning on the “Today” show for weeks.

By contrast, ESPN, the 24-hour sports network, has sent just two reporters to London, plus a handful of blogger-commentators. ABC News is fielding an on-air team of five. CBS News and Fox News are relying on their London bureaus, which have two correspondents apiece. The top anchormen of all four networks are staying home.

What explains the difference in the coverage? NBC News says the Games are such an inherently compelling story that its massive commitment is justified.

“The Olympics are, and have always been, a major international event,” said David Verdi, the network’s vice president of worldwide news gathering. “It’s a huge story of great interest to every part of our audience.”

But it might be a little bit more complicated than that.

The differing approaches to covering the Games may provide an illustration of the forces that sometimes shape the TV-news agenda. In this case, what constitutes “news” seems to depend on not just who’s playing, but also who’s paying.

NBC News’s parent company, of course, has a huge investment in the London Olympics. NBC Universal paid a record $2.2 billion to the International Olympic Committee in 2003 to become the “official” American broadcaster of the 2010 Winter and 2012 Summer games. The fee, which was nearly 50 percent higher than NBC’s winning bid for the previous Summer and Winter games, gives NBC the exclusive right to show Olympic events, starting with Friday’s Opening Ceremonies.

This year, as in 2008 and 2010, NBC will televise thousands of hours of the Games on its main broadcast network and on others owned by NBC Universal’s majority shareholder, Comcast, including MSNBC, CNBC, Bravo, Telemundo and the NBC Sports channel. Even the Comcast-owned E! Entertainment channel, best known for its Kardashian family reality series,will get into the Olympic act; it will feature party coverage and athlete interviews.

And, as in years past, NBC’s news division will be pitching in, too. In the weeks leading up to the Games, NBC News has offered a steady diet of Olympics-related stories.

“Nightly News,” for example, has covered the Olympic torch relay, reported the results of the Olympic trials in swimming and track, and profiled Olympic athletes. One segment featured a dog crowned the world’s ugliest returning home to Britain “just in time for the London Olympics.”

Meanwhile, NBC’s 10 owned-and-operated stations, including WRC, Channel 4 in Washington, will offer more coverage on their local newscasts. Each of the stations will have its own journalist at the Games; WRC’s Dan Hellie will file stories and features for his station throughout the two weeks of competition.

Critics see another agenda in all this. They suggest that much of this coverage is driven not by newsworthiness, but by corporate synergy, in which the news division generates stories to heighten interest in NBC’s prime-time Olympic telecasts.

“There’s no excuse for this,” said Andrew Tyndall, the publisher of the Tyndall Report, which tracks the network news business. “It’s just shameless cross promotion. There’s no journalistic fig leaf to hide behind. It’s free advertising for the prime-time programming.”

Journalists aren’t supposed to promote anyone’s corporate interest, but some lines have been crossed in recent years as competition increases and news profits shrink. Network news affiliates often report as news the results of prime-time singing and dancing competitions aired by their networks; many air interviews on their newscasts with the stars of new sitcoms or dramas that will be shown on their station.

Verdi acknowledges that there’s “a little greater interest and excitement” when a TV news organization is associated with a major event such as the Olympics. “You might see a little more coverage [of the event] on our broadcasts,” he said. “We’re proud of it. It generates greater interest in the news.”

But, he adds, “if the question is, is our editorial process corrupted by an event like this, then the answer is no. We use the same editorial checklist to determine coverage [of the Olympics] as we would for any news event.”

Tyndall challenges that assertion by pointing to the Winter Olympics in Vancouver in 2010. During those Games, in which NBC also had the exclusive broadcast rights, “Nightly News” aired a total of 84 minutes of Olympic-themed news over two weeks — more than four times as much as CBS’s “Evening News” (18 minutes) or ABC’s “World News Tonight” (17 minutes), according to Tyndall’s tracking.

Conversely, when NBC didn’t have the Olympic rights, NBC News’s interest in the story flagged. During the 1998 Winter Olympics — which aired on CBS — “Nightly News” carried just 11 minutes of Olympic-related stories over two weeks. ABC had 18 minutes while “Evening News” ran 41 minutes about the Olympics.

This time, NBC’s rivals say they’ll cover Olympic stories as events warrant. “We’ll neither ignore them nor turn over our entire programming schedule to them,” said Mike Leber, ESPN’s senior coordinating producer. Leber notes that his network and others are handicapped somewhat in their reporting by NBC’s exclusive control over showing events. What’s more, non-rights holders such as ESPN must abide by restrictions on showing copyrighted Olympic footage.

But rival news organizations privately admit their enthusiasm for Olympic stories is tempered by the fact that the Games are being shown by another network. Too much coverage, they say, could drive their viewers to NBC.

“The Olympics are such an all-encompassing event that the other networks can’t ignore it,” said Paul Swangard, managing director of the Warsaw Sports Marketing Center at the University of Oregon. “But the broadcast-rights holder is much more willing to invest its news assets in covering it because they know it will fuel interest that comes back to the bottom line.”

Swangard, a former journalist, said the mingling of news and promotion “is the one place where I start to feel a little queasy about all of this. If credibility still matters to the news division, they should be a cautious partner in that promotional piece of the equation. If people start thinking they’re doing these cheesy stories to fuel the [prime-time ratings], their credibility will be in question once the Olympics are over.”

The London Games could set the tone for several Olympics to come. Last June, NBC signed a deal with the IOC to broadcast every Olympics — summer and winter — through 2020. The $4.4 billion agreement is the most expensive in Olympic history.