Their 2016 rivalry rising, Rubio and Cruz turn to Iowa's powerful evangelicals

Sens. Ted Cruz and Marco Rubio have been sparring over national security and immigration policy as their rivalry intensifies in the Republican presidential primary race. Now their conflict is moving to Iowa and a powerful evangelical constituency that Rubio is making a play for, months after rivals sank roots.

Cruz and Rubio will appear Friday with a group of candidates at a forum hosted by the Family Leader, a prominent Iowa Christian organization that is expected to draw roughly 1,500 people to its event. Also on stage will be retired neurosurgeon Ben Carson, who has led some recent Iowa polls and has a strong evangelical following.

With support from pastors around the state and a recent endorsement from a conservative Iowa congressman, Cruz is in a strong position. But Rubio is about to embark on a five-day tour of the state that will include stops in conservative western Iowa and involve meetings with pastors.

"I can tell you for a fact that there are a lot of pastors taking a second look at Marco Rubio because of his strong positions on national security and the pro-life issue," said Jamie Johnson, a pastor from Story City who worked for former Texas Gov. Rick Perry's failed campaign and is now neutral in the race.

Christian conservative voters traditionally influence the Iowa caucuses because they tend to be organized and motivated to participate. They will also hear Friday from two trailing candidates who achieved past Iowa victories with their help, Mike Huckabee in 2008 and Rick Santorum in 2012, as well as former technology executive Carly Fiorina and Kentucky Sen. Rand Paul.

Carson and businessman Donald Trump continue to hold substantial leads in Iowa polls leading up to the Feb. 1 caucuses, with Cruz and Rubio behind them. The exit of Louisiana Gov. Bobby Jindal, popular with some Christian voters, means some support is up for grabs.

One key endorsement in the evangelical community will be that of Family Leader President Bob Vander Plaats. He said that when he makes a choice, he'll seek to rally his community to make the most impact.

Cruz has spent more time than Rubio in the state and 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 anti-immigration voice in western Iowa, and conservative radio host Steve Deace.

Cruz argues that evangelical Christians, libertarians, tea party supporters and other conservatives must lock arms behind one candidate or risk losing to a more moderate Republican. Deace said Cruz has "done everything it takes to unite the conservative movement."

Cruz is casting Rubio as one such moderate, even though both senators rode the tea party wave of recent years to national prominence and have deeply conservative voting records.

Cruz, for example, accuses Rubio of supporting "amnesty" in his failed 2013 immigration package that would have given immigrants in the country illegally a pathway to citizenship. Rubio casts Cruz as weak on national security because the Texas senator favored limits on government surveillance programs earlier in the year.

Rubio lags Cruz in Iowa campaign time, pastor pitches, endorsements and development of county-by-county support. But he's been rising in the national race and picking up efforts in the state with fewer than 75 days before the caucuses.

"We think we can do really well with evangelical voters," said Rubio spokesman Alex Conant. "I think Marco is uniquely positioned to be able to unite Republicans."