It's hard to believe that Delaware, which only seven years ago was critized as "the corporate state" by Nader's Raiders because of the pervasive Du Pont Co. presence, could more recently be called "antibusiness" by no less a corporate titan than Irving Shapiro, who retires in April as Du Pont chairman.

But not long ago, that's precisely how Shapiro, along with most other big businessmen here, felt about this state's government. The reasons for their unhappiness ranged from what they viewed as radical environmental laws to a soak-the-rich personal income tax structure in the state.

Now, however, the business community here is hopeful that a new day has dawned. So rosy is the outlook for business, in fact, that an ebullient Shapiro recently told a hearing of the general assembly's revenue and finance committee, "Opportunity has knocked and the question is whether we are willing to seize it and build for the future with jobs, investments and new economic activity."

The reason for all the optimism is directly traceable to the aggressively pro-business policies of Delaware's incumbent Republican administration -- headed, appropriately enough, by Gov. Pierre S. Du Pont, a member of the state's first family of business.

Du Pont, a 46-year-old former congressman, last year won 71 percent of the vote to become the first governor of this state in 24 years to be elected to a second successive term. Says Du Pont about the sins of his predecessors. "Delaware started a big spending spree in the late 1960s and early '70s when government was to be the answer to all problems. That, coupled with increased taxes, had a depressing effect on the state's economy."

The policies of the Du Pont administration, which originally took office in 1977, have turned $30 million state deficit into a surplus of $60 million. And Delaware's bond rating, which determines how much interest the state must pay to raise funds, has improved as a result from a lowly BAA to an A-plus. p

The Du Pont administration's most dramatic -- and controversial -- bid to attract new business to the state came last month when the legislature approved its proposal for a radical change in Delaware's financial laws. The new law eliminated usury ceilings on loan interest rates and cut the tax rate for large banking operations based in the state.

For nearly seven decades, Delaware has been the state favored by incorporators. Almost half of Fortune's 500 largest industrial companies are incorporated here because the state is geared to handle the legal complexities of corporate chartering. Now, Delaware is making a bid to become a center of banking, too.

Even before the new banking law was enacted, two major New York financial institutions, Morgan Guaranty Trust and Chase Manhattan Bank, announced they would establish Delaware operations. Other national banks are expected to follow suit, says Nathan Hayward III, acting secretary of Delaware's office of economic development planning, who adds that Washington's Riggs National Bank and American Security and Trust Co. have made inquiries about the law.

In January, First Maryland Bancorp suggested it may move credit operations to Delaware, claiming it lost as much as $3 million a year on its credit card operations because of interest rate ceilings in its state.

This week, Gov. Du Pont and Hayward will take Delaware's story on the road to bankers in Chicago, San Francisco, Los Angeles and Phoenix.

But critics of the plan charge that it actually was masterminded by New York bankers in a power play to force that state to lower its state and municipal taxation of banks. In a similar situation, Citibank is in the process of moving its credit card operation from New York to South Dakota.

Critics say that banks in other states will use the Delaware law as a threat to force their states to remove usury ceilings and reduce bank taxes.

"This is outrageous," says James Boyle, director of government relations for the Washington-based Consumer Federation of America. "At the turn of the century, the railroads wrote the law to enrich themselves. The banks are the modern-day railroads on this one."

New York bank executives shy from commenting on their dealings with Delaware, but Fred Stern an aide to Gov. Du Pont, insisted that, "The banking legislation was written in Delaware."

Stern does allow that the idea began in June 1980, when New York bankers met with Delaware officials as part of a revolt against their state's low usury ceilings. New York legislators apparently got the message, because in November they lifted the usury ceiling.

New York bank taxes remain high, however. There, banks pay taxes of 12 percent to the state and 13.8 percent to the city. Morgan, for example, last year paid city and state taxes estimated at $75 million.

The new Delaware law is aimed at only the top 75 or so national banks, says Hayward. To qualify, a bank must be newly chartered in Delaware with a single office that won't attract customers from the general public -- a provision that protects the home banks. Under the law, a bank must begin with $10 million in capital and raise that to $25 million at the end of the first year.

To attract large chunks of business from jumbo institutions, Delaware has recast its tax on banks to favor size. The new tax on banks ranges from 8.7 percent on the first $20 million of net income down to 2.7 percent on net income in excess of $30 million.

Delaware's biggest bank, Wilmington Trust Co., had taxable income of just $11.2 million last year.

According to Stern, Morgan plans to establish a $4 billion lending operation here to do business with corporations, governments and financial institutions.

A Morgan executive added: "We look at it as a good opportunity to establish a Morgan bank in an interesting environment especially in view of possible change in the laws that restrict interstate banking."

A Chase official said that the bank plans to use Delaware as a base for a national credit card business. Chase-Visa credit card holders now number now number 2.4 million, but are mostly in the New York metropolitan area. Delaware will be used for a planned national marketing effort, said the bank spokesperson.

But big banks are not the only ones seeking benefits from Delaware's new laws. Beneficial Corp., the gaint consumer finance company, is considering a major expansion of its operations in Delaware, according to Finn Caspersen, Beneficial's chairman.

Without a limit on how much interest Beneficial can charge credit card users and other borrowers, says Caspersen, "we can become more aggressive because we can charge according to the market."

He estimates that Beneficial may increase its present Delaware work force of 100 five or 10 times. According to Hayward, Chase and Morgan have said they will bring 360 new jobs to Delaware in the first year.

State officials predict that in the first year the two new banks will produce tax revenues of $2 million, nearly equal to the total of $2.4 million taxes collected from all the Delaware banks last year.

But for Boyle of the Consumer Federation, the new Delaware law sets a dangerous precedent.

Boyle and other critics complained that the bill stampeded through the Delaware assembly with scarcely enough time for the legislators to read it. He testified at the hearing in Dover that the legislation "contains an assortment of deceptive charges that if added to a disclosed interest rate could well mean a 50, 60 or even 70 percent rate of interest."

Among the "Christmas tree of incentives to lure the big banks to Delaware," Boyle cited insurance for which the banks can keep commissions, unlimited default charges, prepayment fees and rate increases that were retroactive on balances outstanding at the time the legislation was made law.

"I think that's just hyperbole," said Hayward of Boyle's comments.

"The federal truth-in-lending [law] covers all banks, no matter where they are located," Hayward said. "There's nothing coercive about the statute. If there was one bank nationwide, that would be one thing. But if customers don't want to do business with Chase out of Delaware, there are plenty of alternatives."

The changes in credit and banking laws are only the latest -- and most controversial -- of a number of measures introduced by the Du Pont administration and aimed at reviving Delaware's seriously sagging economy, which in the 1960s was growing at twice the national average but in the years since has gone flat or worse.

Among the new measures by the Du Pont administration aimed at improving the state's troubled economy and mollifying the business community:

An amendment to the state constitution that limits appropriations of money by the state legislature to 98 percent of the state's official revenue estimate.

"In the old days, estimates were arrived at by someone sticking his finger up in the air," says Hayward, a veteran of Capitol Hill and the federal Office of Management and Budget who is credited with being chief architect of the state's economic program.

Another amendment stipulated that any new tax must be passed with a three-fifths vote of both state houses.

Personal income taxes were rolled back by about 10 percent.

Broadening the economic base away from such cyclical industries as chemical and auto manufacturing, which are the first and second biggest employers in the state.