HOUSTON — For religious conservatives at the Texas Republican Convention, even the song list at Friday’s prayer rally suggested dark days ahead for the GOP.

On stage, a man sang, “While the storm clouds gathered …”

In the audience, Kenneth Kidd mulled his party’s prospects in November.

“We’re going to support McCain,” he said with a distinct lack of enthusiasm. “He may not have been all of our first choice, but he is our choice.”

Evangelicals have been indispensable to Republican presidential candidates since Ronald Reagan in 1980 and were key to George W. Bush’s White House wins.

But many are lukewarm about John McCain, who denounced religious right leaders in 2000 and has struggled to win evangelical support this year.

Some analysts say Mr. McCain has made a political calculation to give up some support on the religious right to broaden his appeal to more centrist voters. Still, if Christian conservatives don’t actively work for Mr. McCain in their churches and neighborhoods, he could have trouble winning in the fall.

“Obviously, the base of the party is not really excited about John McCain,” said Tim Lambert of Lubbock, who heads the state’s largest home-school organization. “I think he’s not reaching out to the base, not reaching out to the evangelicals. Bob Dole made that mistake in 1996.”

This week’s state GOP convention underscored how much work Mr. McCain needs to do if he hopes to rally Christian conservatives. Many delegates explained their support for Mr. McCain in terms of their opposition to Barack Obama.

“I’m going to support McCain and try to help people see the reality of the total picture and how dangerous Barack Obama is,” said state Sen. Dan Patrick, a conservative talk-radio host with a strong evangelical following. “There is no other choice.”

Mr. McCain has had a bumpy ride with evangelicals this year.

He jettisoned the endorsements of two prominent megachurch pastors, including John Hagee, over past controversial statements they’ve made.

This week, some Southern Baptists have questioned the McCain campaign’s absence at the group’s annual meeting. Four years ago, the Bush-Cheney re-election campaign hosted a reception at the event.

Perhaps the nation’s most influential Christian right personality, James Dobson, has served notice he won’t vote for Mr. McCain.

Riding to the rescue on Friday at the state GOP convention was Mike Huckabee, who mobilized born-again voters in the primaries. Mr. Huckabee was surrounded by Republicans who sought autographs and took pictures.

“I think Sen. McCain needs to have a really good speech that gives social conservatives and family and life constituencies of our party a real sense of who he is,” Mr. Huckabee said.

Kelly Shackelford, who heads the conservative Liberty Legal Institute in Plano, had a suggestion of his own for wooing: make Mr. Huckabee the Republican running mate.

Mr. Shackelford pointed at Mr. Huckabee, encircled by well-wishers festooned with political buttons and red, white and blue regalia.

“He could fire them up,” Mr. Shackelford said.