On Tuesday, more than 50 public interest groups sent a letter to the Federal Communications Commission and the Department of Justice outlining their case against the Comcast-Time Warner Cable merger. The letter is a response to Comcast’s filing on Tuesday of its official merger paperwork.

Just last week, Comcast VP David Cohen dismissed concerns about the $45 billion deal, arguing that he hasn’t heard any “rational, knowledgeable voices” objecting to it. Today, we’re putting that myth to bed.

The message in this letter is loud and clear: The organizations fighting on the front lines for our communities ­think this merger is bad news for the American public.

The signers include leading consumer rights, arts, free speech, and open Internet organizations, including Consumers Union, CREDO, Demand Progress, Free Press, the National Alliance for Media Arts and Culture, the National Organization for Women, the Parents Television Council, Public Knowledge and the Writers Guild of America East and West.

Given “the complete lack of any tangible benefits, it’s clear that the union of the nation’s No. 1 and No. 2 cable companies is not good for competition or in the public interest,” the letter reads. Read the full letter and see all the signatories below:

Dear Attorney General Holder and Chairman Wheeler:

The proposed Comcast-Time Warner Cable merger would give one company enormous power over our nation’s media and communications infrastructure. This massive consolidation would position Comcast as our communications gatekeeper, giving it the power to dictate the future of numerous industries across the Internet, television and telecommunications landscape.

In the last four years, Comcast has raised its basic cable rates in some of its markets by nearly 70 percent, while Time Warner Cable has actually cut costs for consumers. But the higher prices and reduced choices that this deal would bring are just the tip of the iceberg.

This merger is, at its core, about broadband, the most profitable and fastest-growing segment of the cable industry. Comcast’s service area would cover almost two-thirds of the U.S., and it would be the only broadband provider that could deliver truly high-speed Internet and pay-TV services to nearly four out of every 10 U.S. homes. This union would give Comcast control over half of the nation’s next-generation broadband customers and more than half of the pay-TV/Internet-bundled subscribers.

The open Internet brings the promise of meaningful competition as it greatly reduces the gatekeeper power that incumbent cable, broadcasting and studio giants like Comcast-NBCUniversal have historically wielded. But this merger — taking place in the vacuum of regulatory oversight of our broadband-communications market — would give Comcast unprecedented control over the Internet. It would also pose a grave threat to media diversity.

Comcast has repeatedly flexed its corporate and political muscles to get what it wants, even if that has meant harming competition, consumers and communities. Around the country Comcast has fought community efforts to bridge the digital divide with municipal broadband networks. It has lobbied statehouses and local governments to undermine public, educational and government access television. It has blocked its customers’ Internet traffic. And it was fined for failing to fulfill the commitments it made to secure approval of its merger with NBCUniversal.

The Comcast-Time Warner Cable merger would give Comcast unthinkable gatekeeper power over our commercial, social and civic lives. Everyone from the biggest business to the smallest startup, from elected officials to everyday people, would have to cross through Comcast’s gates.

Given these clear and present dangers and the complete lack of any tangible benefits, it’s clear that the union of the nation’s No. 1 and No. 2 cable companies is not good for competition or in the public interest. We, the undersigned, representing millions of people from every state, urge you to block this merger.

Sincerely,

Access Humboldt

Alliance for Communications Democracy

Appalshop, Inc.

Austin Airwaves

Broadband Alliance of Mendocino County

California Common Cause

Cambridge Community Television

Center for Media Justice

Chicago Media Action

Citizens for Sanity, Inc.

ColorOfChange.org

Committee for Media Access

Common Cause

Community Media Visioning

Consumers Union

Courage Campaign

CREDO

Daily Kos

Demand Progress

Fight for the Future

Free Press

Future of Music Coalition

Harry Potter Alliance

Holiday Design Group

Independent Arts & Media

Institute for Local Self-Reliance

International Campaign for Responsible Technology

Journalism That Matters, Inc.

Media Alliance

Media Literacy Project

Media Mobilizing Project

Media Working Group Inc.

MoveOn.org

National Alliance for Media Arts and Culture

National Headquarters Studio

National Organization for Women

New America Foundation's Open Technology Institute

OpenMedia.org

Parents Television Council

Personal Democracy Media

PhillyCAM

Prometheus Radio Project

Presente.org

Public Knowledge

Sinsinawa Dominican Sisters’ Leadership Council

Sisters of the Presentation Dubuque, Iowa

Sports Fans Coalition

St. Paul Neighborhood Network

SumOfUs.org

TheUptake.org

TURN — The Utility Reform Network

Women In Media & News

Women’s Institute for Freedom of the Press

Women’s Studies Research Center at Brandeis University

Writers Guild of America East

Writers Guild of America West