Two of the nation's highest-profile Republican governors on Saturday called for more aggressive leadership on America's challenges abroad, emphasizing their support for Israel as they courted powerful Jewish donors.

New Jersey Gov. Chris Christie and Wisconsin Gov. Scott Walker also stoked speculation about their own presidential ambitions as they gave frustrated Republicans advice on how to reclaim the White House in 2016 after losing two straight elections.

The Republican speakers at the Republican Jewish Coalition's annual spring gathering largely avoided criticizing U.S. President Barack Obama by name in remarks that were thick with rhetoric faulting Obama's foreign policy while offering few specifics.

"We cannot have a world where our friends are unsure of whether we will be with them and our enemies are unsure of whether we will be against them," Christie said. "In New Jersey, nobody has to wonder whether I'm for them or against them."

Walker declared that the nation needs a "swift and decisive" foreign policy, while insisting that the GOP must find a presidential nominee from "outside Washington."

The Republican governors, both considering presidential bids, appeared at Republican super donor Sheldon Adelson's Venetian resort casino along Las Vegas' famed strip, speaking inside an ornate ballroom two floors from where gamblers crowded around blackjack and roulette tables.

Two years before the official beginning of the next presidential contest, the lesser-known competition for the GOP's most influential donors is well underway. Establishment-minded fundraisers have long encouraged former Florida Gov. Jeb Bush to run, although many remain skeptical that Bush, the brother of former President George W. Bush, has the passion for a White House bid seven years after leaving office.

Some Republican officials have stepped up pressure on Bush to run in the wake of Christie's bridge scandal, although there remains significant interest in Walker or other prospective candidates in what is considered a wide-open GOP field.

But no single donor's endorsement may be more powerful than Adelson, who is among the 10 richest people in the world. The casino magnate almost single-handedly bankrolled the group behind former House Speaker Newt Gingrich's 2012 campaign. Now, he's casting for a new presidential candidate on whom to shower his millions in campaign cash.

Adelson did not attend Walker's speech, but he was seated directly in front of the podium as Christie spoke.

Earlier in the week, Adelson met privately with Bush, who addressed the Republican Jewish Coalition's senior members at Adelson's company airport hangar. Ohio Gov. John Kasich was the featured speaker during a Saturday luncheon that Adelson attended, along with scores of Jewish donors.

"America must be engaged in the world and we should help the people who share our values," Kasich said in a speech that repeatedly referred to Adelson by name.

Adelson is known for his devotion to Israel, in addition to an aggressive American foreign policy.

Walker conceded that he does not have extensive foreign policy experience, having been focused on state issues as the Wisconsin governor. But he called for a more consistent foreign policy, reflecting upon lessons he learned from raising his family.

"We make sure with both parents and grandparents that we were unified," Walker said. "We didn't waver. We didn't allow our sons to push the line."

The comments come as Obama grapples with the Ukraine crisis. Obama and Russian President Vladimir Putin agreed in a call on Friday to have their foreign ministers meet to discuss a possible diplomatic resolution. Secretary of State John Kerry arrived in Paris on Saturday for talks with his Russian counterpart.

Walker, who is not Jewish, noted that his son's name, Matthew, is from the Hebrew word for "gift from God." He later added that he decorates his residence with Christmas lights and a "menorah candle."

Christie, a Catholic, said he was overwhelmed by displays of religious tolerance during a recent trip to Jerusalem. "I took a helicopter ride from occupied territories across ... and just felt, personally, how extraordinary that was to understand the military risk that Israel faces every day," he said.

The comment about "occupied territories" drew murmurs from some in the audience. The Israeli government and by extension most of Israel's supporters in the U.S. don't consider the West Bank and East Jerusalem to be occupied territory.

The Las Vegas gathering offered a fresh look into the murky and evolving world of campaign finance - a world with few remaining rules for anyone with deep pockets and a deep desire to influence the political process.

The Supreme Court's Citizens United decision in 2010 helped transform a system that had some loopholes but generally required disclosure and limits for individual donors.

With a net worth estimated at nearly $40 billion, Adelson is now free to use a collection of super PACs and nonprofit groups to give and spend unlimited sums of money to influence elections, sometimes without having to disclose his specific role publicly. He donated more than $90 million to political groups in the last presidential election.

Christie briefly addressed his challenges in New Jersey just days after a report he commissioned cleared him of any involvement in the politically motivated plot to create huge traffic jams at the George Washington Bridge last year.

He promised to be more questioning of his staff going forward. "I am going to be responsible for all that happens on my watch," he said.

Meanwhile, Kasich closed his remarks by speaking directly to Adelson.

"Sheldon, thanks for inviting me," Kasich said. "I don't travel to these things much, but this was one that I thought was really, really important."