Do Google and other search engines have a constitutional right to control their own search results?

The answer is yes, at least in the opinion of UCLA law professor and First Amendment scholar Eugene Volokh.

In a report commissioned by the search giant (PDF), Volokh asserts that search results are a type of "opinion" based on what information the search engines believe would be most relevant to their users, according to news site PaidContent. Therefore, the results are protected by the First Amendment.

"Google, Microsoft's Bing, Yahoo Search and other search engine companies are rightly seen as media enterprises, much as the New York Times Company or CNN are media enterprises," Volokh said in the report.

Taking it to its constitutional conclusion, this would suggest that Google and other search engines would be within their rights to exclude certain Web sites and even certain information from their results.

As one example cited by PaidContent, Google would be protected if it decided to exclude the results from business review site Yelp, which has in the past accused the search giant of not playing fair by rigging its results.

Why did Google commission this report?

CNET contacted both Volokh and Google for comment. We'll update the story when we get more information.

The search giant told PaidContent that "we thought these issues were worth exploring in more depth by a noted First Amendment scholar." But the company is also likely looking for some legal ammunition to use in any government showdowns.

Google has been under the microscope of both the U.S. government and the European Union over complaints that it has used its dominant position to tweak its search results to favor its own sites. The U.S. Department of Justice is considering whether to launch an official antitrust suit, while the EU is mulling over a decision in the wake of its own investigation.

U.S. courts have so far tended to side with Google in seeing its search results as protected speech, according to PaidContent. But the company may face a greater challenge in countries where it doesn't have the First Amendment in its corner.