SAN FRANCISCO — A federal judge declared the reciting of the Pledge of Allegiance in public schools unconstitutional yesterday, a decision that could put the issue on track for another round of Supreme Court arguments.

The case was brought by the same atheist whose previous battle against the words "under God" was rejected last year by the Supreme Court on procedural grounds.

U.S. District Judge Lawrence Karlton ruled that the pledge's reference to one nation "under God" violates schoolchildren's right to be "free from a coercive requirement to affirm God." Karlton said he was bound by precedent of the 9th U.S. Circuit Court of Appeals, which in 2002 ruled in favor of Sacramento atheist Michael Newdow that the pledge is unconstitutional when recited in public schools.

The Supreme Court dismissed the case last year, saying Newdow lacked standing because he did not have custody of his elementary-school daughter, on whose behalf he sued.

Newdow, an attorney and a doctor, filed an identical case on behalf of three unnamed parents and their children. Karlton said those families have the right to sue.

Newdow hopes that will make it more likely the merits of his case will be addressed by the high court. "All it has to do is put the pledge as it was before and say that we are one nation, indivisible, instead of dividing us on religious basis," Newdow said.

Legislation passed by Congress in 1954 inserted "under God" into the pledge.

"Imagine every morning if the teachers had the children stand up, place their hands over their hearts, and say, 'We are one nation that denies God exists,' " Newdow said. "I think that everybody would not be sitting here saying, 'Oh, what harm is that?' They'd be furious. And that's exactly what goes on against atheists. And it shouldn't."

Karlton, ruling in Sacramento, said he would sign a restraining order preventing the recitation of the pledge at the Elk Grove Unified, Rio Linda and Elverta Joint Elementary school districts in Sacramento County, where the plaintiffs' children are students.

Gov. Arnold Schwarzenegger issued a statement urging the school districts to appeal.

The order would not extend beyond those districts unless it is affirmed by the 9th Circuit, in which case it could apply to nine Western states, including Washington.

Washington state's Attorney General's Office will study the decision. State law requires schools to lead students in the pledge, said Kim Schmanke, spokeswoman for the Office of Superintendent of Public Instruction, but students can choose to stand silently or decline to say "under God."

Karlton wrote the case concerned "the ongoing struggle as to the role of religion in the civil life of this nation," adding that his opinion "will satisfy no one involved in that debate."

Seattle Times reporter Linda Shaw contributed to this report.

The Los Angeles Times contributed to this report.