Ted Cruz is among the presidential contenders addressing the RJC in Las Vegas this weekend. (AP Photo/Mark Humphrey)

White House hopefuls Ted Cruz and Rick Perry will be among the GOP presidential contenders making a pilgrimage to Las Vegas as the invisible primary for Republican super-donor Sheldon Adelson's millions heats up, hoping to stand out for their unwavering support of Israel and deep skepticism of President Obama's nuclear deal with Iran.

Cruz and Perry are set to speak back to back Saturday morning at the annual meeting of the Republican Jewish Coalition, an opportunity for them to redouble their long-running appeals to some of the most prominent Jewish donors in the country. Adelson, a billionaire casino magnate who sits on the RJC board, is expected to have a front-row seat for most of the confab at his Venetian resort hotel and casino.

Along with Indiana Gov. Mike Pence and U.S. Sen. Rob Portman of Ohio, Cruz and Perry will address a crowd of nearly 800 people, many of whom have given well above the $1,000 minimum to attend the conference. The four speeches make up the only part of the RJC's three-day confab open to reporters, with other big-name Republicans and their aides making more private overtures to the RJC throughout the weekend.

Adelson, who with his wife gave more than $92 million to presidential candidates in 2012, is being closely watched as 2016 hopefuls scramble to firm up financial commitments for what will probably be the priciest-ever race for the White House. Adelson's hawkish defense views, especially on the Middle East, mesh with a GOP field prepared for foreign policy to factor prominently into the 2016 race.

[Washington’s first official 2016 fundraiser, starring Lindsey Graham and Sheldon Adelson]

Cruz and Perry have been unrelenting in their opposition to the United States' emerging agreement with Iran to curb its nuclear ambitions. Cruz was among the original 47 senators who signed a letter to Tehran warning the pact could unravel under a new president, and since then, he has said his only regret was not making his signature bigger. If elected, Perry has promised to scrap the agreement as his first act in office.

RJC spokesman Mark McNulty said donors will not only be listening closely Saturday for how Cruz and Perry plan to stop a nuclear Iran. They also want to hear why the two Texans think believe they can win the general election, he said.

"We've lost twice in a row," McNulty said of Republicans. "So everybody wants to know that anybody who we support can make it through and offer their argument against Secretary [Hillary] Clinton."

In private conversations with Jewish donors, Cruz is making exactly that case — that among his declared and potential rivals, he is both the strongest ally of Israel and the most electable candidate.

"I think that they're strategic and they're looking for somebody who has the best shot at defeating Hillary and also who's going to be a strong advocate for Israel," said Nick Muzin, a senior adviser to Cruz. "For Senator Cruz, it's not lost on them that he's a young, high-profile senator in the Republican Party who's going to have a role in the party for many years to come."

Cruz has been aggressively courting Jewish donors since he become the first major candidate to declare he is running for president last month. The effort, spearheaded by Muzin, has taken Cruz to moneyed enclaves in California, Florida and New York, where he has gained the support of Holocaust survivor and millionaire philanthropist Sam Domb. Cruz also has the backing of Trudy and Stanley Stern, a Manhattan investment banker who serves as a regional president for the pro-Israel lobby NORPAC.

A Perry spokesman did not respond to requests for comment this week on how the former governor has been reaching out to Jewish donors ahead of a likely 2016 run. But Florence Shapiro, a former state senator who sits on the RJC board, said Perry is a "longtime favorite" of the organization, dating back to his efforts as agriculture commissioner to strengthen the relationship between Israel and Texas.

"I would suggest with Perry, he already has a tremendous amount of backers that are Jewish Republicans," said Shapiro, who is part of a "Texas Leadership Committee" supporting former Florida Gov. Jeb Bush. "The idea that he's already got a record, that's already been engaged — that gives him an advantage."

The conference is providing no shortage of fodder for Democrats who have long ridiculed Republicans as pandering to a single donor, hoping to land his largesse. They are quick to point out Adelson's millions could not save Newt Gingrich's 2012 presidential primary bid, let alone that of the eventual GOP nominee, Mitt Romney.

“We fully expect them to be kowtowing to Mr. Adelson, trying to out-conservative one another, trying to convince Mr. Adelson to throw them a lifeline," Democratic National Committee Chairwoman Debbie Wasserman Schultz told reporters Friday on a conference call. "This should not be considered genuine outreach to the Jewish community."

Wasserman Schultz criticized Cruz for his comparison of the fight to defund Obamacare to that against Nazi Germany, saying "those kinds of loose references to the Holocaust are outrageous and unacceptable and make light of one of the worst human tragedies in history."

Neither Cruz nor Perry is expected to linger at the RJC conference after their speeches Saturday morning. Both are due hours later at the Iowa Faith and Freedom Coalition Spring Kickoff in the Des Moines area.