By Dan Gilgoff, CNN.com Religion Editor

Hours after declaring Sunday that he expects to be running for president within a month, former House Speaker Newt Gingrich said he's worried the United States could be “a secular atheist country, potentially one dominated by radical Islamists,” in the foreseeable future, according to Politico.

Gingrich was addressing Cornerstone Church, a megachurch in San Antonio, Texas, led by the Rev. John Hagee, an influential leader among American evangelicals. Hagee's endorsement of then-presidential candidate John McCain in 2008 was plagued by controversy.

McCain ultimately rejected the endorsement over remarks Hagee had made about the Holocaust, in which he appeared to say that Adolf Hitler had been fulfilling God's will by hastening the desire of Jews to return to Israel, in accordance with biblical prophecy.

"God says in Jeremiah 16: 'Behold, I will bring them the Jewish people again unto their land that I gave to their fathers. ... Behold, I will send for many fishers, and after will I send for many hunters. And they the hunters shall hunt them.' That would be the Jews,” Hagee had said in an earlier sermon.

“Then God sent a hunter,” his sermon continued. “A hunter is someone who comes with a gun, and he forces you. Hitler was a hunter."

McCain rejected Hagee’s endorsement of his campaign after learning about the comments in May 2008. "Obviously, I find these remarks and others deeply offensive and indefensible, and I repudiate them,” McCain said at the time.

Hagee then withdrew his endorsement of the Arizona senator, which he had offered three months earlier.

One irony of McCain rejecting Hagee’s endorsement over his Holocaust remarks is that the Texas evangelist leads the Christian Zionist movement. Hagee is founder and national chairman of Christians United for Israel, which features Elie Wiesel and other Holocaust survivors at its events.

Here’s what Gingrich said at Cornerstone Church on Sunday evening, according to Politico:

"I have two grandchildren: Maggie is 11; Robert is 9," Gingrich said at Cornerstone Church here. "I am convinced that if we do not decisively win the struggle over the nature of America, by the time they're my age they will be in a secular atheist country, potentially one dominated by radical Islamists and with no understanding of what it once meant to be an American." The former House Speaker held up his own faith (he converted to Catholicism two years ago) as proof of his undying patriotism. He lashed out at the college professors and mainstream media he says are seeking to wipe out the Founding Fathers' Christian values. And he targeted the judges who he charges are effectively re-writing the Constitution. But Gingrich was mum on his own controversial past, one of martial indiscretions and divorces that have made courting religious conservatives a tall task as he nears a likely presidential run.

Gingrich’s church appearance comes amid a broader campaign to court religious conservatives.

On Monday, Hagee released a statement praising Gingrich's appearance at Cornerstone. “It was such a great honor to welcome Mr. Gingrich to our church, and hear him describe the centrality of faith in our nation,” he said.

The statement also included praise for Hagee and his wife, Diana, from Gingrich.

“It was truly an honor to be with John and Diana at Cornerstone," Gingrich said. "Their dedication to serve is inspirational.”