"As believers, we are called to action; not just sitting quietly and hiding our faith under a bushel but to stand and speak no matter what the consequence," the Texas senator told students at Liberty University. "Religious liberty has never been more under attack."
The Texas Republican and tea party favorite used his appearance here at the Virginia school founded by the late Rev. Jerry Falwell to test a message to young evangelicals, a critical voting bloc for any Republican with White House ambitions.
If speaking at Liberty University is a favorite stop along the early presidential campaign trail for some candidates, writing a book is standard practice for many.
Cruz's literary agent, Keith Urbahn, said Wednesday that the tea party favorite has agreed to terms with HarperCollins. Urbahn declined to confirm a report in the Washington Examiner that the book deal was worth $1.5 million. But he says the number is "close."
"I'm looking forward to the opportunity to share my story and to tell the truth about what's happening in Washington," Cruz, 43, told The Associated Press Wednesday after his speech.
The former Texas solicitor general and the son of a pastor, Cruz urged students to oppose those who would press secular priorities over Christian beliefs.
Roaming the stage in the cavernous basketball arena, Cruz said the health care law is exhibit A of secularism that poses a threat.
"Religious liberty has never been more under attack," Cruz said.
Cruz, who last year led a partial government shutdown over the national health care law, took aim over legal action by the Obama administration against nuns who oppose covering birth control for employees.
He also said business owners of faith are also being forced to provide health coverage that runs counter to their beliefs.
"So am I compelled to carry the gospel of freedom beyond my hometown," Cruz said, quoting civil rights leader Martin Luther King to the gathering of students and faculty in the campus arena.
Should he run, Cruz's faith-centered message could help win him support from a key group.
"He'd get a very strong following almost immediately," said Micah Nihart, a Liberty junior.
Cruz, a first-term senator, has been open about his Christian faith but has tended to focus publicly on constitutional and fiscal issues more than social ones. In recent weeks, he has not shied from social policy.
Last month, Cruz told an influential group of home-school advocates in Iowa that the United States was founded on Christian values. He also told a separate group of anti-abortion rights activists in Washington that they should not compromise on their beliefs.
In coming weeks, Cruz plans to speak to a "Freedom Summit" in New Hampshire, the early voting state, along with potential rivals Sen. Rand Paul of Kentucky and former Arkansas Gov. Mike Huckabee.
Cruz also plans to attend a Free Enterprise Foundation dinner a few days later at The Citadel in yet another early voting state, South Carolina.
The targeted outreach to different segments of the Republican Party is necessary if Cruz is going to expand his appeal beyond the tea party-aligned wings of the GOP that consider him among the favorites at this early stage of the 2016 contest.
Elliott reported from Washington.
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