A prominent Iowa evangelical leader has endorsed Ted Cruz for president, a coup for the Texas senator, who has heavily courted churches and pastors in an effort to win the state's leadoff Republican caucuses.

Bob Vander Plaats announced his endorsement Thursday in Des Moines, calling Cruz a "serious leader for serious times."

Vander Plaats stressed that this was a personal endorsement, not one on behalf of the Family Leader, the influential Christian conservative group he leads. The group's board has decided not to back a 2016 candidate formally, though several others affiliated with the organization joined Vander Plaats in endorsing Cruz.

Vander Plaats said Cruz had built a strong Iowa organization and said he would work to help unite conservatives behind his candidacy.

"When we make an endorsement, our goal is to make that endorsement stick," he said. "We will do whatever it takes to help him be successful to go up against Hillary Clinton." His presumption is that Clinton would win the Democratic nomination.

Christian conservative voters traditionally wield significant influence in the Iowa caucuses because they tend to be organized and motivated to participate. Vander Plaats had been courted by many Republican candidates for that reason.

The Feb. 1 caucuses offer a candidate momentum, though they have not always been a strong predictor of the eventual nominee. Vander Plaats supported former Pennsylvania Sen. Rick Santorum in 2012 and former Arkansas Gov. Mike Huckabee in 2008. Both won the caucuses, but neither won the nomination.

Recent polls suggest Iowa support has grown for Cruz, who has built a deep organization with endorsements from state and local officials and support in all 99 counties. He's also seeking backing from at least one pastor in every county and has been endorsed by Rep. Steve King, a vigorous voice against illegal immigration who represents western Iowa, and conservative radio host Steve Deace.

While Cruz has been on the rise in Iowa, Donald Trump remains a top contender and retired neurosurgeon Ben Carson and Florida Sen. Marco Rubio have significant backing.

Rubio, who has been running an increasingly aggressive campaign against Cruz, was in Iowa on Thursday. While Cruz has spent more time in Iowa and has more evangelical support, Rubio has recently stepped up his visits to the state and recently held several meetings with pastors.

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