Sheldon Adelson was just another billionaire until his money powered Newt Gingrich to a handy win in South Carolina. With a $5 million infusion -- followed by another after Gingrich's victory there -- the Las Vegas entrepreneur who owns casinos and convention centers in the U.S. and Asia went from longtime supporter to kingmaker.

His first donation to the pro-Gingrich Super PAC, Winning Our Future, financed an enormous barrage of negative ads and a half-hour movie that portrayed Republican front-runner Mitt Romney as a heartless corporate raider who sacrificed the jobs of thousands for his own enrichment. In South Carolina Gingrich finished 14 percentage points ahead. The second gift, made in the name of Adelson's wife, Dr. Miriam Adelson, helped make Gingrich competitive in the run-up to tomorrow's crucial Florida primary.

Their gifts demonstrate how the wealth of a single family can change the course of a presidential race. They also show how U.S. relations with Israel, a perennial issue among Republican nominees, may figure even more prominently in this election season.

Miriam Adelson, who met her husband on a blind date, was born in Israel and maintains dual citizenship. Sheldon Adelson has donated tens of millions to Israeli institutions, and has worked vigorously to support hard-liners against those who would accommodate Palestinian claims.

In Gingrich he has found a champion. “There is not a better advocate for Israel,” Adelson, 78, told columnist Gary Rosenblatt of the Jewish Week. In a recent interview Gingrich described the Palestinians as "an invented people," drawing criticism from many but approval from Adelson. "Read the history," Adelson told an audience of hundreds of young visitors to Israel over the recent Hanukkah holiday. The young adults were flown to Israel through a program called Birthright Israel, which Adelson has given more than $100 million.

The Adelsons met Gingrich when he introduced the Jerusalem Embassy Act in 1995,which would have recognized Jerusalem as the capitol of Israel and moved the U.S. embassy to that city from Tel Aviv. While the act was passed by Congress that October, no U.S. president has implemented it, citing security concerns and bowing to the U.N. consensus that Jerusalem is an international treasure, separate from both the Jewish and Arab states.

Gingrich has said that as president he would implement the embassy act on his first day in office.

The Adelsons, who were in Washington in 1995 to lobby for passage of the act, became Gingrich supporters. Later Adelson donated $1 million to Gingrich's American Solutions for Winning the Future, a tax-exempt organization known for promoting oil exploration in the Arctic National Wildlife Refuge.

When Ted Koppel asked Gingrich what Adelson might expect for his money, Gingrich told him, "He knows that I'm very pro-Israel and that’s the central value of his life. He’s very worried that Israel is going to not survive."

Adelson consultant Sig Rogich confirms that view. Adelson, he said, "thinks that little bastion of democracy over there is vital to our interest in the world, and he believes that they're fighting for their lives,  and is going to do everything he can to help them."

Rogich, like others close to Adelson, downplays the magnitude of the super PAC donations, pointing out that Adelson gives more money to other causes, including drug treatment centers in the U.S. and Israel, a private school in Las Vegas and the Yad Vashem holocaust center in Israel, to which he has given more than $50 million.

(The Dr. Miriam and Sheldon G. Adelson Educational Campus in Las Vegas, built with $25 million of Adelson's money, will also be the site of special  evening voting during Saturday's Nevada caucus, arranged so that observant Jews and Seventh Day Adventists can cast their  votes without violating the Saturday sabbath.)

The son of a taxi driver, Adelson grew up in a tough Boston neighborhood and was motivated to earn money from childhood, hawking  newspapers,  running a vending machine business and studying to be a court reporter.

His various ventures didn't always pay off. According to the New Yorker he had earned and lost a fortune twice before 1979, when he created Comdex, a trade show in Las Vegas that expanded rapidly with the growth of the computer industry. (Comdex began holding spring shows in Atlanta in 1983, and for years was the among the city's largest trade shows.)

In 1989 Adelson bought the historic Sands Hotel and opened the 1.2 million square-foot Sands Convention Center next door. Business leaders mocked him -- the city already had the 1.3 million square-foot Las Vegas Convention Center -- but hotels sprang up, and the inventory of thousands of rooms kept both facilities busy. Las Vegas became one of the most important convention destinations in the country, eclipsing Atlanta and a host of other cities.

Said Rogich: "He kind of transformed the town."

Then, in 2004, Adelson opened his Sands Macau in the former Portuguese colony. It was followed by the $2.4 billion Venetian Macau and properties in Singapore. With his Asian ventures, Adelson multiplied his fortune several times over. He is worth $21.5 billion and is the 8th richest man in America, according to Forbes, putting him just behind hedge-fund billionaire George Soros, who is also fond of giving millions to political causes.

Outside of their commitment to Israel, Adelson and Gingrich share an instinct to go against the grain. In one of his infrequent interviews, Adelson told a television reporter that the secret of success is "do things in life the way other people don't do them."

Gingrich, the architect of the Republican Revolution, would almost certainly agree.