Last year Google thrust itself into the network neutrality debate by promoting open-platform wireless handsets. Now it has reentered the fray from the other side.

“Network neutrality” has several competing definitions. Not surprisingly, parties to the argument tend to frame the question in ways that favor their own interests, with the result that people talk past each other.

Our own preferred view dates back to the origin of the controversy. The executives of two major Internet service companies announced they saw nothing wrong with giving some content providers faster service for a higher price. If, for example, were willing to pay the premium, its website would download faster than that of the local bookstore, and thus give customers a better experience, disadvantaging the local bookstore. Network neutrality, in our view, is the principle that says this is wrong – that Internet providers must treat all content providers equally.

Google once seemed to agree, at least in the wireless phone context. It urged the FCC to auction a block of spectrum in which customers could use any compliant handset and access any lawful service. (Elsewhere in the spectrum, cell-phone providers can and do limit handsets and services to those of their partners.) Google subsequently participated in developing the “Android” operating system that makes it easy for independent developers to offer new applications for mobile phones.

This week, though, Google made a controversial announcement. It proposed to locate its own servers on the premises of major broadband Internet providers, with the goal of speeding service to their subscribers.

The Wall Street Journal on December 15 accused Google of changing sides on network neutrality.

Other companies, though, have long collocated servers with the broadband providers. Akamai, Limelight, and others provide a service called “edge caching,” which locally replicates the content of major websites to allow faster access by subscribers. The practice is not widely seen as a violation of network neutrality. For one thing, edge caching is necessary to prevent logjams at popular sites. Today’s Internet could not function without it. For another, the companies that provide edge caching compete with each other in signing up as many websites as possible. Smaller websites work fine without edge caching; larger ones have a choice of providers. Everyone benefits.

Google now says it only wants to do what Akamai and Limelight and the others have been doing for years.

But there is a big difference. Akamai et al. do not manufacture their own content. They merely help with distributing the content of others. Google, with its search engine, YouTube, and dozens of other operations is probably the biggest single content provider on the planet. It has no incentive to share its edge servers with competitors. Despite the company’s protestations, Google’s plans seem to exemplify a fundamental violation of network neutrality.

So far, though, Google faces no legal barriers. Nothing in the FCC rulebook prohibits discrimination in broadband Internet services. The FCC did announce four Internet “principles” back in 2005, but never adopted them as rules, so they may not be enforceable. (We will find out, now that Comcast has appealed the FCC’s use of the principles in ordering it to alter network management practices.) But even then, Google’s plan may not amount to a violation. The most relevant principle just entitles consumers to “competition among network providers, application and service providers, and content providers.” So long as Google is not the only provider on the block, it may be able to discriminate with impunity.

But it can’t do that and still keep saying it supports network neutrality.