AUSTIN, Tex. — When Gov. Rick Perry invited fellow governors to join him on Aug. 6 for “a day of prayer and fasting on behalf of our troubled nation,” some speculated that he was trying to raise his national visibility for a possible presidential run.

Absolutely not, said Mr. Perry, a conservative Christian who described the event, to be held in a Houston stadium, as an “apolitical Christian prayer service” to provide “spiritual solutions to the many challenges we face in our communities, states and nation.”

Whatever the goals, his plan has drawn strong protests from advocates for the separation of church and state, who say an elected leader should not be leading what looks to be, in effect, an evangelical Christian revival. Gay rights groups are also objecting because Mr. Perry placed the event in the hands of conservative religious groups that not only oppose gay marriage but also stridently condemn homosexuality.

So far only one other governor, Sam Brownback of Kansas, who is a conservative Roman Catholic, has said he will attend.