But it was 1980, South Dakota's economy was a mess, and suspicion was an instinct that Janklow could not afford. "We were in the poor house,'' he recalled. "It cost 42 cents a bushel in 1980 to haul wheat. When something's only selling for $2.20 a bushel, you certainly can't afford to be paying almost 50 cents a bushel to ship it.''

Had circumstances been less dire, the news of four urgent phone calls from a New York bank in a single day likely would have been easier to ignore. "Nobody's historically more suspicious of outsiders than South Dakotans,'' Bill Janklow , the former governor of South Dakota, told FRONTLINE in a recent interview.

Robin Stein is a reporter for New York Times Television. She was a member of a reporting team at the Times that won a Pulitzer Prize for Public Service in 2004 for a series on workplace safety.

» A Public Opinion Survey on Using Credit Cards View a 1967 opinion poll that found that 76 percent of Americans felt it was "too easy" for people to buy on credit.

» A Snapshot of the Industry (Map) See how the 1978 Supreme Court decision Marquette Vs. First Omaha Service Corp. affected the locations of the top 10 credit card issuers. Today, all are located in states with very high interest caps or none at all.

» "New York Banks Urged Delaware To Lure Bankers" A 1981 Times article on how Delaware's governor promised banks the ability to charge interest rates not subject to any legal ceiling, to raise interest rates retroactively, to levy unlimited fees for credit card usage and to foreclose on a home in the event of default for credit card debts.

» Graph: Market Share of Top 10 General-Purpose Credit Card Issuers View the effects of consolidation. In 1990, the top 10 general-purpose credit card issuers had a 56.5 percent share of the market. In 2004, the top 10 have an estimated 89.5 percent share of the market.

» "A Little Gift From Your Friendly Banker" How the U.S. credit card usage took off -- a 1970 Life magazine article that was one of the first comprehensive overviews of the industry.

It was just before Christmas when five million cards were dropped by a group of Midwestern banks scrambling to be the first to reach the untapped Chicago market of holiday shoppers. Cards were mailed to convicted felons, toddlers, even dogs. A frenzy ensued. Nightly news reports ran stories about corrupt postal workers feeding stolen cards to organized crime rings. Suburban housewives who had never received cards were getting billed for thousands of dollars of charges.

Still, the first decade of "credit cards drops" had produced little profit and a lot of chaos. People were outraged by what some called usurious temptations, and bankers were flooded by massive defaults. In 1966, an incident dubbed "the Chicago debacle" unleashed an intense wave of public venom.

Before long, banks all over were using credit cards to compete for new customers. But the concept of far-off banks soliciting the masses with open-ended lines of credit challenged the traditions of small-town lending. "We had one bank," Mr. Wriston said of his home town of 30,000. "And the old guy with a green eyeshade gave you credit or he didn't."

"'What is this with people wanting credit?'" Mr. Wriston recalled being asked by his boss at Citibank. "And I said, 'Look, we just put five years of our life in a brown suit carrying an M1 rifle, and we want the refrigerator now.' ''

The industry's ambition was evident from its earliest days. When Bank of America launched the nation's first general-purpose credit card in 1958, it simply dropped 60,000 of them in a mass mailing to residents in Fresno, California. The bank hoped to attract customers with a new type of "revolving" credit line, which could be used for purchases everywhere and paid off over time. The idea was to tap into the pent-up consumer demands of World War II baby boomers.

Those long ago phone calls were a pivotal moment in the ascendancy of America's credit card industry. A notorious loss leader became the most profitable sector in banking, generating nearly $30 billion in net revenue last year alone.

The unlikely alliance would clear the way for Citibank to turn a money-losing credit card operation into a vastly profitable business. "All of their senior people used to say it,'' Mr. Janklow said. "That South Dakota saved Citibank. I believe it did. That South Dakota saved Citibank.''

But the bankers saw opportunity and salvation in the plains of South Dakota. Within days of those first phone calls, a team of top executives arrived from New York with a proposal for Mr. Janklow: If South Dakota would quickly pass legislation that would enable Citibank to move its credit card operations to the state, they would bring hundreds of high-paying white collar jobs to the state.

The bank had lost more than $1 billion on its audacious foray into the credit card business, and the future looked even worse. The trouble, simply put, was that the rate of inflation exceeded the amount of interest Citibank was allowed to charge its credit card customers under New York usury laws.

The calls were from Citibank, which was having a serious problem of its own. "It was very simple,'' said Walter Wriston , then the chairman of Citibank. "We were going broke.''