In a bid to encourage federal oversight of the television-ratings market, News Corp., the media giant that owns Fox News and other networks, is taking its fight against Nielsen Media Research to Washington.

An aggressive new lobbying campaign by the media company is designed to break Nielsen’s monopoly on the ratings market. It comes as Nielsen presses ahead with the roll-out of new technology to measure TV-watching habits in local markets.

Nielsen says that once its new digital method is finalized, it will provide unprecedented accuracy. But News Corp. argues that it will undercount black and Hispanic households — a charge that, if true, threatens to sap millions of dollars in advertising revenues generated by Fox affiliates.

After a year of failing to block Nielsen’s plan through a city-by-city offensive on the legal and public-relations fronts, News Corp. is now going to rely on its ability to leverage its wide mix of audiences in a bid to influence Congress.

To rally minority Democratic lawmakers to its cause, News Corp. is working quietly through a coalition called Don’t Count Us Out, which argues that undercounting black and Hispanic households will cause Fox and other networks to cancel programs aimed at minority viewers.

To rope in Republicans, meanwhile, News Corp. is leaning on the credibility among conservatives of Fox News, the network known for its flag-waving graphics and conservative commentary by Bill O’Reilly.

“Obviously, they’ve made a very, very strong effort to get Republicans,” said an official close to the issue who asked not to be identified. “They’re calling in their favors — because they’re Fox News, because they’ve been with them on the conservative issues, and because they need their help now.”

Jack Loftus, a Nielsen spokesman, said the company’s lobbyists have been put on notice.

“One of their lobbyists told one of ours, ‘Put your running shoes on, because we’re all over this,’” he said. “Every time we go to an office, the other side has been there 10 times.”

Reflecting the bipartisan nature of News Corp.’s team, Howard Wolfson, former executive director of the Democratic Congressional Campaign Committee and now a consultant with the Glover Park Group, spoke on behalf of the company. He said that News Corp.’s only interest is in forcing Nielsen — “a monopolistic provider of essential public information” — to be responsive to industry concerns about its methods.

Wolfson said the company would continue to “press aggressively” for independent oversight. He acknowledged the campaign was still counting on support from minority lawmakers, “but we have broadened our effort as well to members of the relevant committees, on both sides of the aisle and spanning the country geographically.”

At issue in the fight is Nielsen’s new method for measuring viewing audiences in local markets. Local People Meters, as the digital technology is called, have been used for more than a decade to measure national audiences. Nielsen for the past year has been rolling the method out to local markets, to replace the use of paper diaries.

But News Corp. and other critics argue that “fault rates” — that is, errors — from the people meters are higher in minority households, causing such households’ watching habits to be underreported. And if Fox can’t demonstrate that viewers are watching minority-oriented shows, News Corp. argues, the company cannot charge appropriate rates for ads on those programs, meaning that such programs could be knocked off the air.

The media giant originally sought to block the local use of the digital meters entirely. They lobbied minority lawmakers, who in turn successfully pressured Nielsen to delay their plan for New York City.

But the company has since launched local people meters in several markets, including Chicago, Los Angeles and San Francisco. This June, Nielsen plans to add the meters in Philadelphia and Washington, D.C. It is unclear whether News Corp. will attempt to block those plans directly.

News Corp. has enjoyed consistent support from the Congressional Black Caucus and the Congressional Hispanic Caucus. Last spring, the caucuses persuaded dozens of members to sign letters to Nielsen opposing their changes.

More recently, News Corp. shifted its focus, rounding up Republicans to tout its campaign.

Last month, the company’s team of outside lobbying firms gathered Republican signatures for a letter from Rep. Pete Sessions (R-Tex.) to the Federal Trade Commission, requesting the agency “promptly determine what role the Commission can play” in the dispute. He added that “the federal government may also need to be an active participant to ensure that a solution is found.”

A lobbyist for Bockorny Petrizzo, the bipartisan firm headed by Republicans Dave Bockorny and T.J. Petrizzo, e-mailed House staffers in early March, encouraging their bosses to sign up.

“Rep. Sessions wants to send the letter on Fri., which doesn’t give us much time,” one e-mail read. “Some [Energy and Commerce Committee] Members have already signed … Sessions and many of us are working on others.”

The draft letter circulated alongside talking points that outlined the case against Nielsen’s technology. While the letter was new, the talking points were a year old — and they were written by lobbyists at the Glover Park Group, a firm founded by former Clinton administration officials that was brought into the fight with Nielsen to help rally minority lawmakers, Roll Call reported last year.

Glover Park has helped organize the Don’t Count Us Out Coalition, the public face of News Corp.’s advertising and grass-roots blitz designed to bring Nielsen to heel. The coalition describes itself on its Web site as a collection of “minority leaders, community groups, producers, directors, actors and everyday viewers.” But it has acknowledged financial support from News Corp.

Though Glover Park — founded by former Clinton press secretary Joe Lockhart — has been consulting for News Corp. for a year, the firm only registered to lobby for the company last month, listing Joel Johnson, a senior adviser to the 2004 presidential campaign of Sen. John Kerry (D-Mass.), as its lobbyist.

The coalition further beefed up its lobbying activity last month by hiring its first executive director, Cynthia Jasso-Rotunno. She’s a veteran of the DNC’s Hispanic Outreach Project and worked in the Clinton White House.

The coalition has also tapped Minyon Moore, a consultant with the Dewey Square Group, to work as a senior advisor. Moore helped create the anti-Bush group America Coming Together and last summer worked with rap mogul Sean “P. Diddy” Combs on his Vote or Die! Campaign.

To deliver its message, News Corp. has also relied on its own assets. The company’s media outlets have dedicated an unusual amount of attention to the debate as it unfolds, not always disclosing their parent company’s financial stake in the outcome.

The New York Post, for example, wrote about the issue at least18 times last year, describing the technology Nielsen is “shoving … into New York homes” and saying it threatened to “undermine the ratings systems.”

An internal memo circulated among Don’t Count Us Out partners in September outlined possible next steps for the group. The memo brainstorms ideas for “moving the Coalition forward,” including trying to involve “high profile spokespeople” in the campaign, such as the Rev. Al Sharpton, and Bernie Mac, Bill Cosby and Whoopi Goldberg — three black comedians who have had their own TV shows.

It also discussed working with Democrats Sen. Charles Schumer (N.Y.), Rep. Hilda Solis (Calif.) and Rep. Sheila Jackson Lee (Texas) to pursue legislation against Nielsen, “under the umbrella of anti-trust or consumer protection.”

The coalition’s corporate backer may have found a sponsor on the other side of the aisle.

In a March 4 letter to the FTC, Sen. Gordon Smith (R-Ore.), chairman of the Commerce, Science and Transportation subcommittee on trade, tourism and economic development, wrote that if the agency decides it doesn’t have the power to rein Nielsen in, “it is my intention to work with you and my fellow Members of Congress to craft legislation that will empower the FTC to play this role.”

Meanwhile, in an attempt to head off further charges of undercounting minorities, Nielsen has announced its intention to implement recommendations from a task force it formed a year ago to study the issue.

That panel, convened at the suggestion of Rep. Charles Rangel (D-N.Y.), delivered its findings last month, calling for higher samplings of minorities to compensate for their undercounting.

News Corp.’s Wolfson said Nielsen “wouldn’t have done” the review without pressure from the company. “We feel vindicated by the results,” he said. “All of that is to the good, but the process is not over.”