More restraint is in order when it comes to the Obama administrations intent to escalate “antitrust” enforcement against business and enterprise in America.

A skeptical interpretation of antitrust’s realities—up to and including recent campaigns targeting Intel, Google, XM-Sirius; and earlier campaigns against Microsoft and the AOL Time Warner merger, as well as rejected mergers like Echostar/DirecTV—is that antitrust often advances the well being of various species of political predators rather than consumers.

Antitrust is a form of economic regulation. And like all economic regulation, it transfers wealth from somebody to somebody else, often in response to special-interest urging. Partly in recognition of such shortcomings, many economic sectors like transportation and telecommunications were (partly) deregulated and liberalized during the last quarter of the 20th century. But antitrust regulation typically gets a pass. Even in the “new economy,” this century-old smokestack era concept is used to justify constraints and conditions imposed on vigorously competitive modern companies. Antitrust is wrongly seen as being in the public interest, as having a superior role to play in policing markets relative to the alternatives.

In antitrust cases, targeted companies’ rivals have a direct financial interest in the outcome. Appeals to antitrust as a public interest law do not change the fact that private motives of rivals, and even ambitious enforcers, are not simply lurking in the background, but running the show. The idea that antitrust helps consumers and that it has a role to play in the new economy deserves reexamination and challenge.

Under antitrust law, a laundry list of business practices (tying, bundling, discrimination, exclusive deals, and so on) are regarded suspiciously, some outlawed altogether. But business transactions are fundamentally voluntary, non-coercive dealings—unlike the forced antitrust interventions that rivals often seek. From this fresh perspective, one finds that even the most “despised” business behaviors—even collusion and mega-mergers—can be pro-competitive and pro-consumer. To the extent that antitrust regulation strikes down practices that have misunderstood or ignored efficiency justifications, especially in an information-based economy, individuals and society are made unnecessarily poorer.

The list of vilified business practices is long, but needn’t be, and we often try to explain why. If anyone cares about economic recovery and jobs, today’s aim should be to “deregulate to stimulate,” so a list of vilified trustbuster practices would be far more advantageous to consumers.

Wired Magazine editor Chris Anderson has an important new book out, “Free: The Future of a Radical Price.” He focuses on the economics of free services, building on the excellent analysis of thinkers like Mike Masnick (whose 2007 essay, “The Grand Unified Theory on The Economics of Free,” succinctly sums up the concept).

Following up on his book, Anderson has a new op-ed up on CNN.com in which he explores how the emergence of free services in the digital age has raised new challenges for antitrust regulators:

Now Google has Microsoft-like dominance in search and search advertising. What should it not be allowed to do? That question may come to define this era of antitrust law. When [Christine] Varney was confirmed, she withdrew the Bush administration’s report setting relatively conservative standards of antitrust enforcement and declared, “The Antitrust Division will be aggressively pursuing cases where monopolists try to use their dominance in the marketplace to stifle competition and harm consumers…

Varney and her team of economists and lawyers are no doubt tangling with the question of how to enforce antitrust laws in a way that ensures an “even” playing field for competition without causing consumers to lose access to free services that are growing more abundant by the day.

But there’s a more important question that Varney should be asking: what actually constitutes market dominance in the age of free? Is the fact that a firm has a substantial share of a distinct marketplace a reliable indicator of dominance? And if the result of firms achieving high market share is an explosion of free goods and services, is it even in consumers’ interests for government to go after “dominant” firms?

Recent happenings in the tech world suggest that even markets often considered to be dominated by a single firm may be a lot more contestable than we think. Today’s hottest tech news item is that Google is “planning a direct attack” on Microsoft’s venerable Windows operating system. And just a few weeks ago, Microsoft launched its new search engine Bing, accompanied by a massive $100 million dollar advertising blitz.

Hold on a minute. Doesn’t Microsoft have a stranglehold of the operating system market? And isn’t Google in control of the search engine market? Antitrust regulators on both sides of the Atlantic certainly seem to think so, if recent investigations are any indicator.

Yet the top brass at Microsoft and Google must think otherwise, or else neither firm would be devoting such resources to breaking into the search and operating system markets, respectively. Rather than resting on their laurels, Microsoft and Google are competing aggressively, rolling out new and improved services all the time. Consumers are benefiting along the way — even from actions that are allegedly “anti-competitive,” such as Microsoft’s inclusion of bundled software with Windows or Google’s plan to digitize volumes of orphan works.

This dynamic is exactly the opposite of what one would expect from a market in need of “saving” by government trust-busters. In fact, despite Google’s 65% share of search and Microsoft’s 88% share of operating systems, both markets appear to be highly contestable.