The news media are lenses. We look through them. But do we see through them?

Many advances have been made in the kind of media criticism that was being pioneered three decades ago by such analysts as Herbert Schiller, Noam Chomsky, Edward Herman and Michael Parenti. Their groundbreaking work spanned the Carter and Reagan years, when the mass media seemed only capable of critiquing itself from the right.

From the time of the Vietnam War to the Gulf War in 1991 and beyond, the media critics with the biggest media megaphones were overwhelmingly right wing. Whether Paul Harvey on AM radio or The Washington Post's precocious George Will or the emerging cavalcade of talk-radio pontificators, the themes revolved around denunciations of the welfare state, civil rights advocates, domestic opponents of U.S. wars and leftists anywhere — often rhetorically rolled up into the generic rug of "liberals."

But the scope of media criticism in the United States has gradually widened — not nearly enough, and not nearly fast enough, but overall enough to make a real dent in overall public consciousness. Sure, there are still plenty of Americans — stoked by the likes of Rush Limbaugh and Bill O'Reilly — who fervently believe in the Spiro-Agnew-spawned and mass-media-nurtured canard of the "liberal media." But a fundamentally different critique of what ails the media system has emerged.

In essence, that different critique centers on the corporate media as a protector of inordinate corporate power, government secrecy and the forces dragging the USA into one war after another — and then keeping the country at war. Unlike the myth of the "liberal media" (which was launched into orbit by speechwriters for the Nixon administration like Patrick Buchanan and William Safire), the assessment of mass media as a corporatist tool had percolated from the grassroots.

Scholars, activists, thinkers and frustrated observers have gradually coalesced around an understanding of how big money and entrenched interests in government are consistently able to manipulate media coverage of a wide range of issues. Moving and spreading from the margins of the left and academia, the anti-corporate-media critique gained currency and strength. Among the factors was the growth of the media watch group FAIR, founded by Jeff Cohen in the mid-1980s. (I have been an associate of the organization since then.) FAIR, which stands for Fairness and Accuracy in Reporting, continues to persist in its watchdogged endeavor in 2009.

FAIR (on the Web at www.fair.org) has been part of a broad, somewhat amorphous yet increasingly cohesive movement of media activism on behalf of progressive principles. During the past two decades, that movement has affected the national discourse on an array of matters under the general heading of media bias. Like water on a stone, such efforts have had tangible long-term effects, helping to shift the foundation of current public understanding.

In recent years, the proliferation of independent-minded sites on the Internet has added to ways that people can get news, analysis and opinion that run counter to the kind of spin favored by Wall Street and the Pentagon. There's a profusion of the same old media fare online, of course, including plenty that's simply purveying the content of traditional big-money newspapers, magazines and TV outlets. But the barriers to entry no longer amount to millions of dollars just to have a modicum of nationwide media presence.

There's a long way to go, as any click-through of the major network and cable channels can attest. Money still holds most of the keys to the media kingdom. And any effort to counter the dominance of corporate leverage in the news media still has a steep uphill climb ahead.

But the dominant media scripting now has a lot of big cracks in its walls.

Norman Solomon is the author of the book "War Made Easy: How Presidents and Pundits Keep Spinning Us to Death," which has been made into a documentary film. For information, go to: www.normansolomon.com.