There is a fascinating political world out there in America that is almost unknown even to the so-called experts. Ask them about "the Wyoming County Mafia," "the Silo-Stuffers," "the Kiddie Caucus," "the Wood Ticks" or "the Red Right," and even the hottest of the hotshot Washington political pros is likely to look blank.

These nicknames apply to important factions in the legislatures of West Virginia, South Dakota, Michigan, Minnesota and North Dakota, respectively. I learned about them--and about a great many other intriguing matters--in one of the best pieces of political journalism I have read in a long time. It is a 104-page report on "the new face of state politics" in the Sept. 3 issue of Congressional Quarterly Weekly Report.

Why should anyone care about the dynamics of state government, and particularly about the dominant personalities and influences in the 50 state legislatures? Because, as the Reagan revolution in tax policy, social policy and regulatory reform rolls along, more and more of the critical decisions in our domestic government are being made in the state capitols.

When I belatedly started attending the annual meetings of the National Conference of State Legislatures in 1981, it became apparent that the smart operatives in American business already had figured out the power shift. They were there in force, lobbying away.

I've gone to three such meetings now, and each time I have come back with a wider list of contacts and a better appreciation of at least some of the personalities in that arena. But the NCSL annual meetings are so heavily scheduled that there is little time for talking home-state politics.

The CQ report does that job. It tracks everything from the emergence in Alabama of a coalition of teachers, unionists and blacks as the dominant force in the legislature to the importance in Wyoming of the alliance between House speaker Russ Donley and the pro-development Wyoming Heritage Society.

The general observations of editor Alan Ehrenhalt are very much worth passing on. Ehrenhalt finds evidence in many states of a shift of power between the generations, with the older, part-time legislators giving way to younger political activists, many of whom have no other real occupation.

In the transition, he says, lawyers are losing some of their traditional dominance, and teachers--who find the typical legislator's under- $20,000 annual salary not bad by their standards--are becoming much more important.

In the South and West, the conservative Democrats who dominated legislatures in the past are losing their clout. Reapportionment is whittling away the number of rural districts from which they come and the "old-boy networks" on which they depended for influence are being sundered by the forces of demographic and political change.

In the North and East, on the other hand, it is big-city, labor-allied Democrats who are slipping in influence. The emerging leaders, in all sections, tend to be younger, more independent Democrats, often with suburban districts, who are liberal on environmental and social issues but not automatically so on economic questions.

Republicans are having a hard time in the legislatures, for a variety of reasons. Even in the Reagan year of 1980, they won only 39 percent of the legislative seats. And in 1982, their share declined to 37 percent. Ehrenhalt thinks the GOP problem is likely to be long-lasting.

"In most states where they were strong in earlier years," he notes, "Republicans drew most of their candidates from a pool of successful small-town lawyers, grain farmers, real-estate and insurance agents. . . . Skeptical of government activism . . . they were willing to take a few months a year to do their part to prevent Democrats from carrying government . . . too far.

"Those same Republicans are far more reluctant to spend eight or nine months of the year in legislative session and a sizable portion of each election year campaigning--all to participate as part of a minority in a state government process dominated by liberal Democrats . . . and for a relatively small salary in most states."

Hard up for candidates, the Republicans are turning to retirees, to the wealthy and-- increasingly--to women, who have given them some of their more striking victories in recent years. But women legislators, as we all know, have policy ideas of their own, sometimes outside Republican orthodoxy.

Too much attention focuses on the White House, too little on the changes taking place in the heart and base of our government at the state and local level. Ehrenhalt and his colleagues have shown us just how large that change really is.