Family Research Council President Tony Perkins gestures during a news conference  last summer  in Washington. (AP Photo/J. Scott Applewhite)

Tony Perkins,  president of the Family Research Council, declined during an interview Friday to commit to back Donald Trump even after the New York billionaire secures the official GOP presidential nominee.

During a taping of C-SPAN's "Newsmakers" show Friday, Perkins openly worried that a Trump nomination could depress turnout of Christian conservative voters, a pillar of GOP electoral success.

Perkins, who is personally backing Texas Republican Sen. Ted Cruz, said he foresees a contested convention coming up for the GOP, a party he said is already badly fractured.  If Trump won the nomination, he said he was unsure what he would do. Is it possible Perkins, who has stumped for past nominees, would back the Democratic candidate for president? That's unlikely, Perkins said, smiling. "I could actually be on a hunting trip [in] November of 2016," he joked.

If the New York real estate mogul secures the Republican nomination in Cleveland, Perkins said, "it would require sitting down with Donald Trump to see what his pathway forward was" on matters such as Supreme Court and vice presidential preferences, positions on key policy issues and his past record. Although Mitt Romney wasn't his first choice for president in 2012, Perkins said, he came to believe Romney as president would act in ways consistent with the positions he espoused during the campaign. However, other evangelical Christians remained unconvinced and stayed home, contributing to Barack Obama's margin of victory. That reticence among conservative faith voters could be a factor again in 2016, he said.

"I am very concerned about what may happen in the general election," Perkins said in the interview, which will be broadcast Sunday, "especially once a lot of focus is placed on Donald Trump  -- his personal affairs, past positions, his conduct, various things. I think that is likely to have an impact on the way evangelicals respond in the general election."

Evangelical Christians have been targeted for support by GOP hopefuls in recent presidential election cycles.  Former Arkansas governor Mike Huckabee, a preacher himself, banked on support from that community, which enabled him to win the Iowa caucuses in 2008. Cruz, the son of a pastor, has built his campaign around wooing support from Christians. A concerted effort was made by some evangelical leaders in December and January to block Trump's rising popularity among self-identified evangelicals. It didn't work very well.  Trump won the white evangelical Christian vote in the South Carolina primary  and in the Nevada caucuses.

The list of evangelical Christian leaders blasting Trump has continued to grow -- but so has evangelical support for his candidacy. In eight of the presidential primaries conducted so far, Trump won more evangelical voter support than Cruz, according to polling data.  "Many of those who tell pollsters they are evangelical may well be drunk right now," wrote Russell Moore, president of the Ethics & Religious Liberty Commission of the Southern Baptist Convention in a Washington Post column last month. For his part, Perkins said the definition of evangelical Christian may have been stretched this year.  Perkins said much of Trump's success comes from voters who are fearful and frustrated, "particularly with a Republican party that has over-promised and under-performed."