In 1998, Dick Cheney pulled off what was widely seen as a business coup. Ending years of fruitless talks, Mr. Cheney arranged a merger between Halliburton, the company he ran, and its chief rival, Dresser Industries, creating the world's largest oil field services and construction company.

Mr. Cheney, the chief executive of Halliburton, initiated the deal while on a quail hunt with his counterpart from Dresser. The negotiations that followed were so amicable, the companies dispensed with the close scrutiny of each other's businesses that is usually part of a merger, a Dresser official said.

Some key Dresser executives quickly came to regret that decision, present and former company officials say. They were startled to learn after the deal closed that several of the major projects negotiated by Mr. Cheney's management team were much less healthy than they appeared on Halliburton's books and were racking up significant losses. The newly merged company was hit with several hundred million dollars of unexpected losses, including an estimated $100 million on a single pipeline project in South America begun on Mr. Cheney's watch, according to company insiders and others in the oil industry.

The Dresser merger was the biggest deal of Mr. Cheney's five years at Halliburton and the losses that arose soon afterward were one of several missteps in a business record that has become part of his political resume since he was nominated to be the Republican candidate for vice president. The Bush campaign has defended his multimillion-dollar retirement payment from Halliburton as fair compensation for a job well done.

''The American people should be pleased they have a vice-presidential nominee who has been successful in business,'' said Karen P. Hughes, communications director for the campaign of Gov. George W. Bush.

But just how successful Mr. Cheney was as a chief executive is a matter of considerable dispute, judging by a broad survey of his record that included interviews with present and former company executives.

Some praised him for doubling the size of the company through mergers and a growing government business that has made Halliburton the nation's fifth-largest military contractor.

Asked to assess Mr. Cheney's performance, Halliburton's vice chairman, Donald Vaughn, said he deserved a ''clearly superior'' grade. ''Mr. Cheney was anything but a status quo man,'' Mr. Vaughn said. ''He changed Halliburton and the popular judgment is he changed it for the better.''

Other executives, however, said Mr. Cheney failed to keep a sufficiently tight rein on the company's aggressive pursuit of overseas energy projects and road-building work in the United States. Some Wall Street analysts, too, described Mr. Cheney's performance as little better than average.

A spokesman for Mr. Cheney declined to make him available for an interview and referred questions about his tenure at Halliburton to the company.

Mr. Vaughn, the last president of Dresser, acknowledged in an interview that there had been ''overall surprise'' with the losses that emerged after the Dresser merger. Most of them, he said, came from contracts on the Halliburton side of the ledger.

Mr. Vaughn blamed the reversals on an industry downturn caused by plummeting oil prices in late 1998 and on the complexity of the projects and said neither he nor his Dresser colleagues felt deceived. ''No one was flimflammed,'' he said. ''Absolutely not.''

Halliburton's stock price, often regarded as a gauge of executive performance, rose sharply in Mr. Cheney's early years at the company, but it lagged its competitors in the final year and a half of his tenure.

There is a presumption in business that a chief executive is broadly responsible for everything that happens in his company, for better or worse. Last year, the company's board of directors withheld bonuses from Mr. Cheney and his management team, which had failed to meet the board's financial targets for 1998 and 1999.

David J. Lesar, the man Mr. Cheney picked to run the company's day-to-day operations, said his boss was ''hands off, very much a delegator'' whose main role at the company was cultivating clients and setting strategic direction. ''He and I talked almost every day,'' Mr. Lesar said. ''On major types of things, I would tell him what the decisions were.''