MADISON, Wis. - To pray or not to pray?

That's the issue government leaders across the country are facing after a federal judge ruled that the National Day of Prayer set for May 6 was unconstitutional.

The ruling can't take effect until all appeals are exhausted, but that's not stopping atheists and prayer advocates from firing off letters, e-mails and even planning to put up billboards to convince state and local leaders across the country to see things their way.

Nothing's changing in Topeka, Kan., says Mayor Bill Bunten.

"Some of these judges have lost their way," Bunten said. "Every day is a day of prayer in most Kansas lives, whether they are Christian or Muslim or Jewish or whatever, and to say that a prayer day is illegal is just ridiculous. That judge better go back and read some history about how this country was formed. Next thing you know we won't be able to sing 'God Bless America.'"

The ruling raised a furor among religious advocacy groups, who say the day has become an American tradition. And the announcement this week by President Barack Obama's administration that it would appeal galvanized atheists, who are trying to persuade officials not to attend local events. Their campaigns illustrate the persistent tensions over any combination of religion and government.

Congress established a national prayer day in 1952 and in 1988 set the first Thursday in May as the official day for presidents to issue proclamations asking Americans to pray. Many state and local officials follow suit on that day.

Two years ago, the Madison-based Freedom From Religion Foundation sued the federal government, alleging the day violated the separation of church and state. U.S. District Judge Barbara Crabb ruled April 15 that the day amounts to a call to religious action. She included a caveat, though, that said her ruling would have no effect until all appeals are exhausted.

A day after Crabb's ruling, the Alliance Defense Fund, an Arizona-based group of Christian lawyers, fired off letters to mayors telling them it has no bearing on prayer day activities.

The Madison foundation, including co-president Annie Laurie Gaylor, was busy with similar activity on Friday.

Employees prepared letters to governors and the mayors of more than 1,000 cities urging them not to participate in prayer day. They also were drafting an online petition where people could urge Obama to honor Crabb's ruling and "leave days of prayer to individuals, private groups and churches, synagogues, mosques and temples."

"Whether or not we win in court, I want to win in the court of public opinion," said Gaylor. "This law is based on lies and bad history."

John Bornschein, executive director of the National Day of Prayer Task Force, said atheists try to sway government leaders from participating in the prayer day every year, but are being more aggressive. He called such efforts a waste of money that could go toward the poor.

"We're an office full of patriots," Bornschein said. "To see bickering over these sorts of things, it's not a positive environment for people who need encouragement now more than ever."

Green Bay Mayor Jim Schmitt said he issues a proclamation every year recognizing the prayer day and attends a prayer breakfast with his name on the invitation. Nothing will change this year, he said.

Carl Brewer, mayor of Wichita, Kan., said the city recognizes prayer day every year. Officials often take prayer breaks and read Bible passages at events. He said this year will be no different.

"Prayer, he said, "is the foundation of the Midwest."