"People from other faiths did volunteer, which is great," said one of Greece's lawyers, Brett Harvey of the Alliance Defending Freedom in Scottsdale, Ariz. "The town has no problem with any of that."
The case will test the impact of the court's changed composition over the past decade and the ideological shift that has left Justice Anthony Kennedy as the most likely deciding vote. The justices will probably hear arguments in November or December.
The court has taken up religion cases only sparingly since Roberts became chief justice in 2005. In perhaps the biggest ruling, a 5-4 decision in 2010, it revived a federal law designed to protect a Christian cross erected as a war memorial in a national preserve.
"The goal of avoiding governmental endorsement does not require eradication of all religious symbols in the public realm," Kennedy wrote in the court's lead opinion in that case.
Supporters say legislative prayer has been a widespread practice since the country's founding — and not something that was called into question when the First Amendment, adopted in 1791, barred the "establishment of religion" by the government. The vast majority of state legislative bodies open the day with some kind of prayer, as do both houses of Congress.
"It's part of our historical tradition and the fabric of our country," said Vince DiPaola, the founder of the Lakeshore Community Church, an evangelical congregation, who has delivered the prayer at town meetings at least seven times.
Critics say that tradition doesn't mean government bodies can favor one religion over others. Ayesha Khan, who represents the challengers, says at least half the state legislatures take steps to ensure the invocations are nonsectarian.
"It's not unusual for legislative bodies to ask guest prayer-givers to pray in an inclusive fashion, and that's exactly what we're asking for here," said Khan, a lawyer with Washington-based Americans United for Separation of Church and State.