SPARTANBURG, S.C. - Republican presidential candidate Ben Carson announced the endorsement of 15 South Carolina "faith leaders" during a news conference Wednesday evening, a rollout that comes as the campaign struggles to find steady footing after a nose dive in national polls.

"I want to thank all of the ministers for their courageous stand," Carson told reporters on stage at the Upward Star Center. "I am of the firm belief that our country is moving in the wrong direction, and a lot of that has to do with the fact that we're giving away the very values and principles that made us into a great nation so that we can be politically correct."

In recent weeks, Carson has struggled to move beyond intense scrutiny over his grasp of foreign policy and national security issues, which have taken heightened importance since the terrorist attacks in Paris. Those questions have taken a dramatic toll on Carson's poll numbers; a national survey of Republican voters released on Wednesday by Quinnipiac University showed that his support has fallen by 7 percentage points, putting him now in third place.

Carson spokesman Doug Watts said he is "not surprised" by the downward trend in several national polls.

"We've been the target of a lot of unfair and unfavorable publicity the past month, yet we still poll in the top ranks nationally, and frequently #1 or #2 in many state polls," Watts told the Post in a written statement. "We are excited to bear down in the final 60 days before the Iowa Caucus where we expect to do well."

Carson's support among white Christian evangelicals - a crucial bloc in early-voting Iowa - has also slipped, down from 32 percent last month to just 19 percent. Many of those voters appear to have thrown their support behind Sen. Ted Cruz of Texas, who ties with Carson nationally and is ahead of him in Iowa.

The campaign has made moves to counteract that narrative that it is in trouble. Last week, Carson's team announced that it had brought prominent evangelical Johnnie Moore into the fold as a "special faith adviser."