By Glen Johnson

WASHINGTON - The Federal Communication Commission's decision yesterday to relax the rules on media ownership triggered a wave of condemnation from the Democratic presidential contenders, with most of them declaring the change would undercut diversity in the nation's broadcast and print media.

Senator John F. Kerry of Massachusetts labeled the 3-2 decision, split between the commission's Republican and Democratic appointees, "a complete dereliction of duty." He pledged to file a Senate resolution to reverse it on the grounds it may harm small businesses.

"Today's wrongheaded vote by the Republican members of the FCC to loosen media ownership rules shows a dangerous indifference to the consolidation of power in the hands of a few large entities rather than promoting diversity and independence at the local level," Kerry said in a written statement. "The FCC should do more than rubber stamp the business plans of narrow economic interests."

Howard Dean, the former governor of Vermont, said the vote was "a crushing blow" to diversity and local ownership, which he argued would be more attuned to local breaking news, especially weather hazards.

The commission lifted a prohibition on newspapers owning a television station in the same media market. In addition, the commission re-wrote rules governing local TV ownership so a single company can own two television stations in more markets and three in such major markets as New York.

Another of the Democratic candidates, Senator John Edwards of North Carolina, said he would co-sponsor legislation to reverse the decision.

The product of a rural upbringing, Edwards complained last week in a letter to FCC chairman Michael Powell: "People in rural communities and small-town America have distinctive interests, and local stations offer programming that responds to these interests. . . . By undercutting this diversity, the FCC's new rules will do a disservice to all Americans."

Senator Joseph I. Lieberman of Connecticut took a more reserved posture. He labeled the vote a "cause for concern" and pledged: "As president, I will watch carefully to see if these rules work to the detriment of the American people and, if they do, I will take necessary action. Once again, the administration has demonstrated that the public interest is not their highest priority."

A fifth candidate, Senator Bob Graham of Florida, said "this wrong-headed action is an abdication of the federal government's responsibility to protect our democratic values of openness, competition, and diversity."

Through an aide, Representative Richard A. Gephardt of Missouri called the decision "anticonsumer and anticompetition."

Statements from the three remaining candidates - Representative Dennis J. Kucinich of Ohio, former Senator Carol Moseley Braun of Illinois, and New York activist Al Sharpton - were not immediately available.

The FCC's ruling has a special historical ring in the Boston media market because of wide speculation that it may lead to the repurchase of the Boston Herald by media baron Rupert Murdoch. The Herald's current owner, Patrick Purcell, has dismissed such talk.

At a time when Democrats controlled the House and Senate, Senator Edward M. Kennedy flexed his muscle in 1987 in an attempt to force Murdoch into selling the Herald, which he then owned.

As recounted in "Edward M. Kennedy," a biography of the senator by Adam Clymer, Kennedy disliked his coverage in the Herald and responded by asking Senator Ernest "Fritz" Hollings of South Carolina, then chairman of the Senate Commerce Committee, and an Appropriations subcommittee that provided the commission's funding, to enforce a 1975 rule banning cross-ownership of newspapers and TV stations in the same market.

At the time, Murdoch owned WFXT-TV, Boston's Channel 25, and the Herald under a temporary commission waiver.

"Hollings inserted an amendment that prohibited the FCC from even considering a change in the rule and barred any new waivers to anyone who already had one," Clymer wrote. While a federal Appellate Court later ruled the Hollings amendment was unconstitutional, Murdoch soon announced he would sell WFXT-TV.

Ultimately, he decided instead to sell the Herald to Purcell. Today Murdoch's News Corp. owns WFXT-TV.

Kennedy spokeswoman Stephanie Cutter said yesterday: "Senator Kennedy still feels strongly that it's wrong to allow monopolies in media markets, because the free exchange of ideas in a democratic society is so essential."