Melissa Phillip - Houston Chronicle , Associated Press
Natasha Solce of Houston reads from the Bible Genesis, Chapters 1 through 16 as she and other volunteers read scripture at Reliant Stadium Friday, Aug. 5, 2011, in Houston in preparation for The Response prayer event to be held Saturday. The entire Bible was being recited twice by the volunteers who were stationed throughout the stadium in every section of seating and were assigned a portion of the Bible to read.

HOUSTON — Though not yet a declared candidate, Texas Gov. Rick Perry is putting his faith under the national spotlight as a White House prospect with an important conservative constituency all to himself.

Perry on Saturday was addressing a prayer rally that he has spearheaded while weighing a campaign for the 2012 GOP presidential nomination.

The governor has said the event is not political but rather aimed at rallying the nation to a Christian unity during difficult times. Still, he was reaching thousands of religious conservatives, many of whom vote in Republican primaries, especially in early voting states Iowa and South Carolina.

As the rally got under way, a few thousand evangelical Christians, most from Texas, were on the floor at Reliant Stadium. More than 8,000 had said they planned to come to the stadium, which seats 71,500 and was the site of the 2004 Super Bowl. Buses were still arriving at the stadium at midmorning.

Perry was scheduled to address the audience around midday. Thousands of values voters were following the event on the Internet and in more than 1,000 churches around the country.

"You didn't come here to listen to speeches," Luis Cataldo, a Kansas City, Mo., pastor, said in opening the event. "You came here to pray. Jesus wants to hear you. Jesus wants to hear your voice."

Perry was not expected to take questions from the scores of news media covering the event, aides said.

"With the economy in trouble, communities in crisis and people adrift in a sea of moral relativism, we need God's help," Perry said in a June video when he announced the event, called The Response USA. "That's' why I'm calling on Americans to pray and fast, like Jesus did and as God called the Israelites to do in the book of Joel."

The rally is financed by The American Family Association, a Tupelo, Miss.-based group that opposes abortion and gay rights and believes that the First Amendment freedom of religion applies only to Christians.

Although Perry invited all the nation's governors, members of Congress and the Obama administration, it was not clear whether any top elected officials besides Perry would attend. Kansas Gov. Sam Brownback had said he would attend, although event organizers said Friday it was unclear whether the Republican governor would be there.

Perry, who has said he is considering a presidential run in part out of a religious calling, is expected to announce his plans sometime after Saturday's event. He plans to travel to South Carolina next Saturday, when several of the declared Republican candidates for president will be in Ames, Iowa, for that state's presidential straw poll, a closely watched test of campaign strength in the leadoff caucus state.

Some Republican strategists have said Perry would be better off to identify himself as a fiscal conservative, touting Texas' recent job gains, as he approaches a decision that could shake up the race. Nodding to evangelical voters before entering the race could send the signal he's not the pro-business conservative some activists have said is lacking in the 2012 GOP field.

"He doesn't need to bow to the Christian right because he already has his bona fides there," said Iowa Republican Doug Gross, who was a top backer of former Massachusetts Gov. Mitt Romney's 2008 campaign but has been cool to support him again.

Iowa state Rep. Josh Byrnes, a Republican, called the event "strange" and said Perry ought to make his national debut as an economic conservative. "Up here in Iowa, people have been saying this isn't quite what we're looking for now," Byrnes said.

Nor is it clear the event will help Perry with Christian voters in Iowa, an influential bloc of the state's Republican caucuses.

Pastor Cary Gordon of Sioux City's Cornerstone World Outreach church said his church will likely webcast the event, although Gordon, an influential GOP activist in Iowa, does not plan to support Perry.

Gordon said he objects to Perry's comments, in light of New York's legalization of gay marriage in June, that the state had the right to enact such measures.

"All of our rights come from God," Gordon said. "Rick Perry becomes the poster child for the problem because he is suggesting men grant men rights."