WASHINGTON — When Supreme Court Justice John Paul Stevens steps down this summer, he will leave the court — long dominated by Protestants — without one for the first time in its history.

That historical oddity has reopened a low-key debate as to whether the religion of a justice matters, and whether President Barack Obama should consider the faith of his next nominee.

Absent Stevens, the Supreme Court will be composed of six Catholic and two Jewish justices. Two of the three candidates said to be the favorites for the nomination — Solicitor General Elena Kagan and federal appeals court Judge Merrick Garland — are Jewish. A third, federal appeals Judge Diane Wood, is Protestant. The White House says there are at least six others under consideration.

Mark Scarberry, a law professor at Pepperdine University, said that having Protestant representation was key in a country where about half of Americans identify themselves in that manner.

Without it, "you could have an undermining of confidence in the court, a sense of a lack of participation," he said, "especially when the court is dealing with high-voltage issues like religious freedom. It would help to have someone who has a sympathetic point of view on the court."

But Jay Sekulow, who often argues on behalf of evangelicals before the high court and serves as chief counsel for the conservative American Center for Law and Justice, calls such talk a distraction.

"The religious background and beliefs really are not relevant to that process. It's how the judge views himself and his role in government," Sekulow said. "The fact that someone shares my theology ... I'm more concerned that they share my judicial philosophy."

Others believe that even discussing the issue is problematic.

"People think it's especially wrong to talk about religion," said Ann Althouse, a professor at the University of Wisconsin Law School. "Religion is a private matter."

But she added that Obama has repeatedly emphasized that life experiences are valued traits for nominees.

"There is an idea that there is more to judging than looking at sources of law," she said, "and Barack Obama has specifically emphasized that part of the judicial role."

Pamela Harris, head of Georgetown University's Supreme Court Institute, said religion was just another factor that should be considered. "It's hard for me to see religion as especially different than all the other things that presidents take into account, such as race and gender," she said.

The current composition of the court is a distinct shift from the past. Only a few Catholic judges — and even fewer Jewish ones — served on the court until the late 20th century.

But religion has been intertwined with the nomination process. President Dwight Eisenhower famously nominated William J. Brennan Jr. to the court in 1956 in a bid to woo Catholic support for his re-election campaign.

Now, the court's conservative wing — Samuel A. Alito Jr., Anthony M. Kennedy, John G. Roberts Jr., Antonin Scalia and Clarence Thomas, all appointed in the last 25 years by Republican presidents — is entirely Catholic. Obama's first nominee, Sonia Sotomayor, makes six.

That is a sizable number considering that the United States has elected just one Catholic president, John F. Kennedy, who had to reassure voters that his faith would not interfere with his duties as president.