Robert A. Mosbacher, a Texas oil mogul who served as a chief fundraiser for five Republican presidential campaigns and who as Commerce Secretary under President George H.W. Bush successfully promoted the North American Free Trade Agreement, died of pancreatic cancer Sunday at The University of Texas M.D. Anderson Cancer Center in Houston. He was 82.

The son of Wall Street investor who pulled out of the market before the crash of 1929, Mr. Mosbacher spent his life amid opulence and privilege.

With $500,000 in seed money from his father, he started the Houston-based Mosbacher Energy Co. and built it into one of the largest private energy concerns in the country. By avoiding risky projects, the company managed to outlast the 1980s oilfield bust that put some larger corporations out of business, and Mr. Mosbacher amassed a personal fortune estimated at more than $200 million.

In addition to his business success, Mr. Mosbacher won a U.S. men's sailing championship in 1958 and world championships in 1969 and 1971. He appeared on the cover of the May 19, 1959 Sports Illustrated with his brother, Emil "Bus" Mosbacher Jr., who skippered two teams to victory in the America's Cup.

His East coast heritage and Gulf Coast riches helped make Mr. Mosbacher a successful fundraiser among the Republican elite, and he brought in millions of dollars for presidential contenders, including Gerald Ford in 1976 and John McCain in 2008. His tightest political connection was with fellow Texan Bush, for whom he worked on three presidential races -- including in 1980, when Mr. Mosbacher convinced Bush to drop out early enough to be considered for the vice presidency.

While the fundraiser's third marriage, to the vivacious socialite Georgette Mosbacher, made the couple a frequent subject of Washington's society and gossip pages, his closeness to the president gave him unusual sway as the Secretary of Commerce, rarely considered an influential position.

"At Cabinet meetings, he's like the 800-pound gorilla," a senior official in the Reagan administration told the Wall Street Journal. "He can sit where he wants."

As head of the traditionally protectionist Commerce Department from 1989 to 1992, Mr. Mosbacher became one of the Bush Administration's leading proponents of free trade with Mexico and a key contact for senior Mexican officials as they negotiated NAFTA. With the same gregariousness and affability that made him a top fundraiser, Mr. Mosbacher toured the country to stem concerns that free trade with Mexico would result in lost jobs at home.

The agreement, which radically rewrote the economic relationships between Canada, Mexico and the United States, was ceremonially signed in 1992 before becoming law two years later under Bill Clinton.

Mr. Mosbacher presided over the 1990 Census and its contentious aftermath, drawing fire when he refused to adjust the count despite a follow-up survey that showed the original effort had missed some 5.3 million people.

Civil rights leaders said the decision disproportionately affected minorities and the poor. It also triggered a lawsuit filed by New York City and other large cities that sought to force the adjustment of the count. In 1996, the U.S. Supreme Court issued a unanimous decision in favor of Mr. Mosbacher, affirming that he had made a "reasonable choice in an area where technical experts disagree."

Robert Adam Mosbacher was born on March 11, 1927, in Mount Vernon, N.Y. He grew up commuting between a Park Avenue apartment in Manhattan and a suburban home in Westchester County.

He graduated from Washington & Lee University in 1947 and set off for Texas with his young wife, the former Jane Pennybacker. By 1954, he had found his first million-dollar natural gas field. His approach was conservative, with one oilman friend telling Forbes magazine, "Even at the height of the boom, when everybody else was going full blast, Bob ran his business as if we were still in a mediocre period."

In 1970, Jane Mosbacher died of leukemia and Mr. Mosbacher was counseled in his grief by Bush and James Baker III, who had also recently lost his wife to cancer. The trio would go on to the highest levels of government together.

Drawn into politics in the 1960s by his friendship with Bush, who won a seat in the U.S. House in 1966, Mr. Mosbacher was named finance co-chairman for the Republican Party in 1976. Finding the Ford presidential campaign's coffers nearly empty, he sent entreaties to 1,700 people and quickly raised $14 million -- $2.5 million more than the Carter campaign.

"An ordinary response would have been 5 percent to 10 percent," Robert Odell, who worked on the campaign, told Forbes. "Something like 50 percent sent money back. It was incredible. And they did it not so much because it as for the President but because Bob asked."

Mr. Mosbacher's second marriage, to oil heiress Sandra Gerry Smith, ended in divorce in 1982. He then married Georgette Paulsin, a flashy redhead 20 years his junior whose arrival in DC was called "a one-woman Normandy Invasion" by The Washington Post.

The pair attracted attention as one of the city's more dashing couples. He was a tanned and handsome sailor who kept a boat moored in the Bahamas and she, an unabashed beauty with a penchant for low-cut dresses and wealthy men, was the chief executive of La Prairie, a maker of expensive face creams.

The couple divorced in 1998, making headlines again when he stopped paying $32,000-a-month alimony payments. He claimed she violated a non-disparagement clause in their divorce agreement; she sued; they eventually settled.

"There are a lot of things that are exciting and charming about her, but my efforts to talk to her were, unfortunately, mostly failures," Mr. Mosbacher told The Post after their divorce. "Georgette is on 'send,' not on 'receive.' "

Georgette Mosbacher, who went on to become a major Republican fundraiser in her own right, kept a $9 million Fifth Avenue apartment in New York and a palatial beach home in Southhampton. She wrote several books, including "It Takes Money, Honey: A Get Smart Guide to Total Financial Freedom."

Mr. Mosbacher left his Commerce post in 1992 to raise funds for Bush's reelection campaign. It was a period during which the GOP intensified anti-gay, anti-abortion rhetoric, requiring Mr. Mosbacher -- whose daughter Diane is a lesbian -- to walk a delicate line between the personal and political.

At the Republican National Convention that year, conservative television pundit Pat Buchanan declared "cultural war" on homosexuals and delegates waved placards reading "Family Rights Forever/Gay Rights Never." In support of his daughter, Mr. Mosbacher agreed to meet with gay leaders, reportedly making the Bush administration the first to be briefed on gay issues.The party's evangelical right pilloried Mr. Mosbacher. His daughter told The Post, "Dad said … he didn't know what else family values is if it's not supporting your kids and who they are."

Survivors include Mr. Mosbacher's fourth wife, Michele McCutchen Mosbacher of Houston; four children from his first marriage, Robert Mosbacher Jr. of the District, Diane Mosbacher of San Francisco, and Kathi Mosbacher Wheeler and Lisa Mears, both of Houston; three stepsons, Donald Cameron Duncan III and Robert Gerry, both of Houston, and Lloyd Gerry of New York; one sister; and seven grandchildren.