A battle under way between internet-search giant Google Inc. and the federal government could have huge implications for online privacy on one hand and the government’s ability to regulate access to what it considers objectionable on the other. A government effort to revive the 1998 Child Online Protection Act (COPA), ruled unconstitutional by the U.S. Supreme Court, is behind the current court fight.

Google Inc. is rebuffing the Bush administration’s demand for access to what millions of people have been looking up on the internet’s leading search engine–a request that underscores the potential for online databases to become tools for government surveillance.

The Bush administration says it wants the information to determine how often pornography shows up in online searches as part of an effort to revive COPA. The act was struck down two years ago. But since then, the composition of the high court has changed, making it unclear how the Justices might rule now.

Mountain View, Calif.-based Google has refused to comply with a federal subpoena first issued last summer, prompting U.S. Attorney General Alberto Gonzales to ask a federal judge in San Jose to order Google to hand over the records.

The U.S. Department of Justice wants a list of all the search terms users typed into Google’s search engine during an unspecified single week–a breakdown that could conceivably span tens of millions of queries. In addition, federal investigators seek 1 million randomly selected web addresses from various Google databases.

In court papers the San Jose Mercury News reported on after seeing them Jan. 18, the Bush administration depicts the information as vital in its effort to restore COPA. The rejected law would have required adults to use access codes or other ways of registering before they could see online material deemed objectionable, and it would have punished violators with fines up to $50,000 or jail time. The high court ruled that technology such as filtering software might protect children better.

The matter is now before a federal court in Pennsylvania, and the government wants the Google data to help argue that the law is more effective than software in protecting children from online porn.

Google told the Mercury News that it opposes releasing the information because it would violate the privacy rights of its users and would reveal company trade secrets. Nicole Wong, an associate general counsel for Google, said the company will fight the government’s efforts “vigorously.” “Google is not a party to this lawsuit, and the demand for the information is overreaching,” Wong said.

Every other search engine served similar subpoenas by the Bush administration has complied so far, according to court documents. The cooperating search engines weren’t identified in the documents, but Yahoo Inc., which runs the internet’s second-most used search engine behind Google, confirmed on Jan. 19 that it had complied with a similar government subpoena.

Although the government says it isn’t seeking any data that tie personal information to search requests, the subpoena still raises serious privacy concerns, experts said. Those worries have been magnified by recent revelations that the White House authorized eavesdropping on U.S. civilian communications after the Sept. 11 attacks without obtaining court approval.

“Search engines now play such an important part in our daily lives that many people probably contact Google more often than they do their own mother,” said Thomas Burke, a San Francisco attorney who has handled several prominent cases involving privacy issues.

“Just as most people would be upset if the government wanted to know how much you called your mother and what you talked about, they should be upset about this, too.” The content of search requests sometimes contains information about the person making the query.

For instance, it’s not unusual for search requests to include names, medical profiles, or Social Security information, said Pam Dixon, executive director for the World Privacy Forum.

“This is exactly the kind of thing we have been worrying about with search engines for some time,” Dixon said. “Google should be commended for fighting this.”