A US District Court judge dismissed a lawsuit March 27 that accused Chinese search engine Baidu of illegally suppressing free speech by censoring information about democracy movements in China on the internet. The decision raises some unsettling questions about the world’s dependency on a handful of search engines.

The group of activists who brought the suit said Baidu’s government-mandated censorship was preventing Baidu’s users in the US from seeing their work, and thus violated their right to free speech under the US constitution’s First Amendment. Judge Jesse M. Furman’s paradoxical conclusion was that forbidding Baidu from censoring results would be a violation of its right to free speech, as the ruling states:

The case raises the question of whether the First Amendment protects as speech the results produced by an Internet search engine. The Court concludes that, at least in the circumstances presented here, it does. Accordingly, allowing Plaintiffs to sue Baidu for what are in essence editorial judgments about which political ideas to promote would run afoul of the First Amendment.

The topic, he notes, has “been the subject of vigorous academic debate” but has received little attention from courts, except two rulings with “sparse analysis” that came down on the same side he did.

He cites instead legal precedents in which a newspaper and a gay rights parade stand in for the internet search engine. They were being sued to include information or participants they didn’t want to. He concludes: “as a general matter, the Government may not interfere with the editorial judgments of private speakers on issues of public concern.”

The difference between a monolithic internet search engine like Baidu or Google and a newspaper or a private parade, though, is that most of Google’s billions of users or Baidu’s estimated 530 million won’t encounter another comparable source of information (like a newspaper) with similar reach, and they can’t create their own alternative (like the marchers who were excluded from the parade.)

The dominant search engines are far ahead of their nearest competitors. And people tend to use one search engine exclusively, whereas newspaper readers are likely to see news from other sources too (radio, TV, the internet, even another newspaper). To wipe a topic or person from the leading search engine is, therefore, effectively to wipe them from much of public discourse.

Here’s a look at how much Baidu dominates the Chinese internet market, for example, from EnfoDesk via ChinaInternetWatch:

In the US, Google has 67% of the internet search market, followed by distant second Bing with 18.1%, according to ComScore. Google is even more dominant in some European countries, like the Netherlands, where it has a 94% market share. It leads in Latin American markets as well.

Wiping a person or topic from the public discourse is of course what the Chinese government intended with its censorship on democracy movements. But the issue is bigger than China’s censorship. If, like Baidu, Google were to decide to censor individuals or companies or their work from the internet for any other reason, they would practically disappear from the public discourse in many countries, killing business, personal and other opportunities. And according to Judge Furman’s ruling, Google would be within its rights to free speech to do so.