LAS VEGAS (CBSMiami/AP) – If you’re trying to figure out which GOP heavyweight is considering a presidential run in 2016, watch Las Vegas this weekend as the candidates try to win the support of billionaire Sheldon Adelson.

In 2012, Adelson bankrolled the campaign of Newt Gingrich, partially out of loyalty. Now, Adelson is ready to back whoever he believes has the best chance of winning, instead of who is his friend.

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The four-day Republican Jewish Coalition meeting is already being called the “Sheldon Primary” as potential presidential candidates look to win support from the GOP’s top money men.

The event will feature a who’s-who of candidates including: Jeb Bush, Chris Christie, Scott Walker, John Kasich, Dick Cheney, John Bolton, and House Speaker John Boehner.

But don’t expect a lot of details from the event as the details are being guarded as closely as the dark money lists that power mega donors on both sides of the political spectrum.

Bush is set to address donors Thursday evening at a private airport hangar.

Adelson, known for his devotion to Israel, is the Republican Jewish Coalition’s most influential benefactor. He donated more than $90 million to political candidates and super PACs in the last election cycle. His total donations may never be quantified publicly because various politically active groups that operate as nonprofit organizations don’t report the source of their funds.

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Several Republican operatives who regularly speak to reporters were reluctant to comment on Adelson and his role in the next presidential contest. Those who did offered general praise of his generosity beyond politics.

Charlie Spies, who led the super PAC that backed Romney in 2012, said Adelson and his wife “are generous philanthropists that back causes ranging from educational to pro-Israel to political. It is often lost in the hype over their political giving that there are schools, museums and nonprofit organizations around the world with the Adelson name on them.”

Adelson gave the pro-Romney super PAC $15 million in four months before the last presidential election.

A Walker spokesman offered only a vague explanation when asked why the Wisconsin governor was attending the Las Vegas meeting.

“The governor remains focused on 2014 and sharing his common-sense conservative message with like-minded leaders,” Walker campaign spokeswoman Alleigh Marre said.

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Adelson is considered one of the 10 richest people in the world, with a net worth exceeding $40 billion, according to Bloomberg Billionaires Index. He is also the driving force behind the push to bring the Republican National Convention to Las Vegas in 2016.