Chicago — New Hampshire Gov. John H. Sununu is right up front about it. ''If it's a good idea, we'll plagiarize,'' he says with a smile. When elected last fall, Governor Sununu inherited what he insists was a ''fiscal mess'' - a budget deficit, a very low bond rating, and a 9.5 percent unemployment rate.
He knew that in Delaware, fellow-Republican Gov. Pierre S. du Pont IV had inherited a similarly bleak fiscal picture when elected in 1977, but had managed to turn Delaware around. Governor du Pont was promptly tapped for advice and has been in New Hampshire at least a half-dozen times since last fall.
Taking several cues from Delaware's experience, including the use of medium-range financing and drawing on the expertise of state business leaders, Governor Sununu says the budget now is headed for a surplus. New Hampshire's bond rating has improved. And unemployment is a low 3.5 percent.
More than ever, the 50 states are swapping ideas that work. This give-and-take is one of the purposes of a conference such as the Republican Governors Association (RGA) meeting in Chicago this week. And it's a solid sign that the states are trying with new vigor and some success to find innovative answers to common problems.
Many here - and not only the governors - argue that the states now are making more of the critical domestic policy decisions than is Washington.
''Many things work very well at the state level as good models, but people just don't hear about them,'' says Pat Choate, an economist with TRW Inc. and a job-training expert who spoke at the RGA meeting.
Citing the need to ''customize'' job training to available jobs, Dr. Choate says Missouri, Tennessee, Oklahoma, and South Carolina are on the ''cutting edge'' of that effort. And Delaware, he says, has just completed an experiment, patterned after the GI Bill, which links unemployment-insurance benefits with job training and counseling help.
In interviews here, a half-dozen of the governors attending the RGA conference insist that the state of the states has seldom been better.
''For a while it was assumed that everything important was being done in Washington, but now it's almost the reverse,'' says Tennessee Gov. Lamar Alexander. He notes that 27 states are looking at different ways to pay higher salaries to teachers who do the best job.
''Most of the important and rewarding work in public policy today is going on in state legislatures,'' says Governor Alexander. ''It's making the governor's job, which used to be more ceremonial 20 years ago, much more interesting.''
''Federalism is alive and well and prospering,'' agrees Delaware's Governor du Pont. ''Just look at education. All 50 states have task forces which have recommended everything from restructuring teacher salaries to increasing graduation requirements. . . . It's the states who are becoming the economic planners and stimulators . . . and we're realizing that our success lies in our cooperation.''
President Reagan's one-time pitch for New Federalism - a plan to shift more dollar and decisionmaking power back to the states - is heard no more. States, worried that new federal dollars would not match new responsibilities in the President's health and welfare swap, thwarted the plan.
But several governors, including Illinois Gov. James R. Thompson, insist that federalism still exists. He cites the increased number of federal block grants sent to the states and wider state discretion on how the funds can be spent. ''More power and more resources are flowing to the states, though nobody's talking about it,'' he says.
''New Federalism is kind of a dry, academic term but, in fact, for the first time in 50 years there has been a cautious turning back to state governments. It's been a dramatic change,'' agrees Pennsylvania Gov. Richard L. Thornburgh.
But Washington Gov. John Spellman insists that any increased power states now enjoy is largely the result of a vacuum. The federal government, he says, has pulled back from such issues as education, prison reform, and job training.
''More initiatives and solutions are occurring at the state level, but it's because of federal inaction, not federal action,'' says Governor Spellman.
Most governors single out the new Job Training and Partnership Act (JTPA), successor to the Comprehensive Employment and Training Act (CETA), as the best example so far of a Washington-funded program which allows states enough elbow room to decide how to spend the money and administer the programs. ''It's one of the best steps in the right direction,'' says Missouri Gov. Christopher S. Bond. ''It's a vast improvement over CETA,'' agrees Iowa Gov. Terry Branstad.
But Oregon Gov. Victor G. Atiyeh, new RGA chairman, insists the state fight for more power from Washington continues. ''We're finding more flexibility, but it's not anywhere near what we'd like to have to do things that are innovative and different,'' he says. ''I don't think Reagan's message has crept down through the bureaucracy, and Congress apparently doesn't believe in federalism at all.''