RONALD REAGAN IS not the first president to have his failings lurch to center stage in the second summer after his election. Lyndon Johnson's summer of 1966, Richard Nixon's summer of 1970 and Jimmy Carter's summer of 1978 were all times of tribulation-cum-recalculation. So, too, with The Great Communicator -- and small wonder.

Depending on which pollster (if any) you trust, 30 to 50 percent of Americans worry that the country is in a depression. Sixty to 70 percent again believe the United States is "on the wrong track," nearly as many as in the worst days of Jimmy Carter. President Reagan's job approval has plummeted 20 to 25 percentage points in little more than a year, roughly the same as Carter's did. GOP hopes of "creeping realignment" have collapsed. The mid-1981 thesis that Reagan has reasserted the presidency and triumphed over Congress and Washington interest groups is no longer a subject of serious capital conversation.

Not surprisingly, then, there's scarcely a White House unit or Cabinet department that hasn't quietly begun rewriting the script for Act Two next January. The name of the game now is going to have to be a recognition that bringing back the true-blue verities of yesteryear -- Packard Sedan Economics and Horatio Alger Do-It-Yourself Sociology -- hasn't worked, and that Reagan's swing electorates of 1980, From Dixie fundamentalists to Plains Wheat farmers, were never looking for that sort of stuff anyway.

What will emerge from this crise de regime is of course impossible to predict, but one intriguing possibility is that Reaganism and the Republican Party may begin to tilt toward the kind of government activism of the early Rooseveltian or other centralizing molds.

History contains many precedents for such a transformation. At the extremes, for example, Dennis Mack Smith's new biography of Mussolini is a timely reminder that the Italian leader began his regime in 1922 with a Reagan-like program of tax cuts, balanced- budget notions and opposition to government intervention in economic affairs. Mussolini even had a finance minister, Albert de Stefani, who pushed an early version of the Laffer Curve. Before long, however, Mussolini was drawn in the direction of statism and economic planning, along with much else.

Obviously, I'm not suggesting that Reaganism would ever go to such extremes, only that circumstances may require movement toward a degree of government intervention that's alien to the president and his wistful dream of restoring Norman Rockwell America.

That, at least, is the direction that would result if Reagan and his aides finally recognize the nature of their own constituency, the precarious historical context of their policies, and -- to put it bluntly -- the extent of their 1981 misunderstanding of America. Indeed, the Reaganite crisis stems from 18 months of electoral, economic and institutional misperceptions of a magnitude probably not seen (if one excludes Watergate) since the 1965-67 Johnson years.

Take the notion that the 1980 election results reflected a stunning "conservative" victory. Think again. The Reaganites seem not to understand how much of their own coalition is actually post-conservative -- a conservative politics transformed by the heirs of William Jennings Bryan encroaching on those of William McKinley.

Bear in mind that Ronald Reagan got somewhat under 51 percent of the 1980 vote, up just 2 points over Gerald Ford -- and that the movement in pivotal voters and constituencies between Ford and Reagan is what tells the tale. Consider: George Gallup reports that among business and professional people, Reagan actually dropped a point below Ford. And he also ran behind Ford in many of the more prosperous Northern suburbs. So where did Reagan run notably ahead of Ford? The answer is simple: among insurgent constituencies spurred by cultural, religious and economic frustration.

Reagan ran 15 to 20 points ahead of Ford, for example, among white Southern Baptists. Orthdox Jewish sections of Brooklyn showed a comparable trend, as did rural right-to-life Catholic counties of the Upper Farm Belt and some urban ethnic precincts.

The other major pro-Reagan trend groups came out of >vocational insurgencies: farmers (especially in the wheat counties from the Texas Panhandle north to the Canadian line, where 20- to 30-point Reagan gains over Ford were common); loggers, defense workers and military families (the trend around military bases and military aircraft plants was often 10 to 20 points); and workers in a few industries or areas (Ohio's Mahoning Valley) particularly angered by Carter policies.

There's precious little support among these constituencies for the Great Supply-Side Economic Mandate. Indeed, the notion of conservative economics as the dominant election impetus defies credibility. Not only did Reagan trail Ford among business and professional voters, but in many industrial areas most hurt by hard times, Democrat Jimmy Carter maintained or increased his majorities between 1976 and 1980. Take Erie County, N.Y., home of congressional supply-side drumbeater Rep. Jack Kemp, where blue-collar workers are supposedly champing at the bit for applied Reaganomics. Erie quintupled its Democratic presidential majority between 1976 and 1980, from 9.000 to 45,000.

Sure, the 30-odd percent of the electorate that regularly votes Republican undoubtedly did (and still largely does) support business- tilted and upper-bracket-tilted policies of the sort implemented since Inauguration Day. But the pivotal electorates, the key trend groups of 1980, were generally responding to other stimuli. If anything, most of the major shift-groups were populist; theirs was no mandate for upper-bracket tax relief or highhinterest rates. Sic semper psephological myopia.

If Libertarians have a compulsion to get the government out of the bedroom, newly ensconsed Republican presidents have a compulsion to get it out of the boardroom. Over the 60 years prior to January 1981, six out of seven GOP administrations managed to "squeeze" liberal economics enough to help trigger a recession by their second year, just in time for the congressional elections. Inasmuch as Reaganite planners took office either unaware of or determined to ignore this electoral-economic history, the record now stands at seven out of eight. Scratch 1982.

Comparable shortsightedness prevailed on two other dimensions. Insufficient attention was paid to the great probability that the heady economic ideologies empowered by the Reagan victory -- principally supply-side and monetarism -- would be incompatible in practice. The chastening record of Margaret Thatcher's first year and a half in office was available to Reaganites in January 1981. Under Britain's Conservative aegis, constituencies and philosophies wound up compromised into an ineffective economic mix of tax reduction and high interest rates (soon repudiated -- as Reaganomics would itself be by mid-1982 -- by purists on both sides).

Moreover, around the time of Reagan's taking office, evidence was likewise available in Canad, Israel and Europe that conservative regimes elected in the mid- tolate-1970s "turn to the right" had been unable to bring their troubled local economies under control.

Alas, these flashing yellow and red lights were ignored. Hot-rodding Reaganites preferred to claim that supply-side or monetarist theory (or both) held the promise of a uniquely resurgent U.S. economy. Panaceas were promised, partly out of reverie -- the notion that the clock could be set back and the United States returned to a late adolescent position on the Laffer Curve.

A third miscalculation was also central. As late as mid-1980, many top Republicans were all too well aware of the weakness of U.S. political and governmental institutions. Ronald Reagan himself contemplated a substantial reshaping of the executive branch and the role of the vice president when the job was dangled before Gerald Ford. Other GOP leaders toyed with announcing a bipartisan conservative Cabinet before the election. Still others, recognizing the continuing erosion of the political parties, looked beyond the narrow framework of the Republican Party to the idea of organizing Congress on bipartisan conservative coalition lines.

Serious democrats broached parallel ideas. Daniel Patrick Moynihan proposed having members of Congress in the Cabinet, and White House Counsel Lloyd Cutler suggested that the United States ought to shift to a quasi-parliamentary system.

But when the votes were counted in November, Republicans abandoned these caveats in the ecstasy of Reagan's 10-point victory margin and their surprise capture of the Senate. Reformist awareness was submerged in hubris. This president could triumph with new ideas alone. The Iron Triangle of interest groups could be beaten. No bipartisan coalition would be necessary. Congress could be managed, and the GOP could ride "creeping realignment" to a New Majority all by itself. A new economic philosophy could do the job. A major mistake, of course.

As of today, the results of all these miscalculations have left the Reagan administration pretty far up a pretty unpleasant creek with a pretty small paddle. One is reminded of 1965- 67, when the Johnson administration also grossly misread its 1964 mandate -- mistaking repudiation of Barry Goldwater for voter endorsement of Johnsonian domestic and global ambition. The Democrats brought in endless numbers of smart young professors, planners and consultants, people pushing ideas Kansans and North Carolinians never remotely contemplated in casting 1964 Democratic ballots.

Ronald Reagan's challenge is not dissimilar. However, instead of LBJ's poverty theoreticians, social engineers, paper-money PhDs, Ford Foundation gurus and Pentagon defoliationists, Reagan's problem is with eggheads who want impractically minimalist government -- former assistant directors of the Tupperware Institute for the Defense of Economic Freedom, think-tank luminaries dedicated to the disestablishment of the federal government role, professors with umpteen articles published on deregulating the toothbrush industry or leasing the national parks to Howard Johnson's. The interaction of the president's inbred biases with their theories has been as out of step with public thinking as the cacaphony of 1965-67. A useful direction has been pursued too far.

In the same way, just as there was no reason 10 or 15 years ago to credit the populism of Ford Foundation planners or Nader's Raiders just out of Harvard Law School, the self-portrait of today's supply-side and deregulation advocates as populists -- with blue- collar America hanging on the fulfillment of their every promise! -- makes little sense. For all the attempts to bathe Reaganomic theory in Howard Jarvis tax-revolt imagery, true populism simply doesn't enter the bloodstream of national debate via the editorial page of the Wall Street Journal, draw inspiration from the 1920s tax cuts of Coolidge- Hoover Treasury Secretary Andrew Mellon (against whom Hoover Era populists brought impeachment in 1932), or win its principal literary support from a book -- George Gilder's "Wealth and Poverty" -- by a young man guided in loco parentis by David Rockefeller.

Arguably, the essential bond between the 71-year-old president and many of his young conservative theoreticians is one of nostalgia and restorationism. Often, countries passing onto the downslope of history go through a phase of trying to recreate their zenith years -- in some cases imperial, in our case the halcyon Coolidge commercial era the president is always citing.

Today's challenge, of course, is that restorationism hasn't worked -- in economic policy, in the "New Federalist" attempt to return power to the states, or in the attempt to turn back a larger chunk of American decision- making and social responsibility to private enterprise. More activist, pragmatic policies must evolve -- and soon.

Second-wave Reagan policymaking is going to have to face up to all these realities, and especially to the fuller implications of the nature of the Reagan coalition. The new post- conservative era is one in which conservatism has radicalized, becoming more and more an insurgent credo. Yardstick after yardstick -- geographic, cultural, institutional -- confirms the transition. No longer an establishmentarian credo, conservatism by 1980 had become heavily influenced by outsider forces-- the New Right, cultural single-issue groups, tax revolt populists, TV-radio preachers, religious fundamentalists, arch-supply-siders (publicist Jude Wanniski and his self-proclaimed "Wild Men"), and Sun Belt superpatriots.

Reagan was the perfect candidate to draw it all together, because his own Sun Belt politics, party insurgency, anti-Washington outsidership, religious- and social-issue sympathies and supply-side/gold standard economics both mirrored and encompassed all the radical transformations. By his easygoing manner and relaxed persona, Reagan muted their harsher implications and contradictions. The public took comfort and relaxed.

So his generalized call for an American renaissance and restoration provided a nostalgic tent with room for everyone and everything. For foreign policy hawks, the country would return to the era of Pax Americana; for supply-siders, the Treasury would take a stab at Coolidge economics; for business, a return to the days before Ralph Nader; for the New Right, a return to the days before the Supreme Court rejected God and embraced abortion; and for the neoconservatives, a chance to dance on the political grave of the New Class and recall the days when students at City College in New York revered their professors.

And therein lies todays volatility. So eager were Americans to turn away from Jimmy Carter that the instabilities and contradictions of the Reagan coalition made little difference. With various radical transformations little perceived, the terms of the Reagan synthesis were never debated. But as the 1980s unfold, that no longer holds. Radicalized conservatism seems to be imploding, and the question is: Where do we go from here?

November's elections need not be a major point of digression. Unless the economy weakens again notably in the next few months, the congessional returns are not likely to yield a very decisive result. The media teem with statistics suggesting the public has little real faith in either party, and Democratic gains are likely to fall well below what current indices of economic hardship would historically suggest.

Similarly, it's not hard to imagine a three- way race in 1984 -- a match between a Republican and Edward Kennedy, with John Anderson in the middle -- in which the GOP might retain the White House despite an unimpressive record. U.S. politics are straining toward a larger-than-party redefinition -- Gary Hart and Paul Tsongas would say neoliberal; I would say post-conservative -- and the trick is to try to look beyond party politics and circumstances to lay out the social, economic and institutional trends likely to dominate the mid- to late-1980s.

The common implication of the trends I see -- and here is where the president's philosophy will have to bend most to adjust -- is greater reliance on central government. Despite Reagan's nostalgia, the prospect is that the federal government will continue to consume its 21-23 percent of the GNP rather than be pushed back to 19 percent or so in a triumph of new-Coolidgeism.

Ironically, even many of the goals pushed by the political right -- a rapid national defense buildup, a crackdown on crime (and other elements of permissivness), stepped-up U.S. foreign economic competition and trade -- will require a maintenance or even expansion of government power.

True, there are a few areas where reduction of government involvement seems to be a clear trend -- partial deregulation of some industries, less sociological meddling in school districts and metropolitan housing demographics, devolution of some administrative and regulatory authority to states and localities. But the dominant forces of the 1980s, it seems to me, will push the smaller-government crowd aside.

Consider the economy. As Stage One Reaganomics grinds itself to pieces, even Ronald Reagan's own Commerce Department is working up preliminary approaches to a National Industrial Policy to guide national industrial priorities and resource allocation. Increased government activity on behalf of U.S. trade, undercut recently by the strong dollar, also seems certain. And then there's the likelihood that the decline of the national transportation infrastructure -- roads, bridges, mass transit and the like -- will bring forth a major, government-financed and government-superrebuilding effort.

Also, economic policy failures -- notably, the impossibility of the federal budget process and White House frustration with Federal Reserve Board management of the money supply -- must also generate some increased centralization of economic planning power in the executive branch. Major changes will have to be made in the mechanics of government, including quasi-parliamentary shifts toward more executive-legislative policy collaboration. Inflationary eras almost always centralize power; the evidence of history is weighty.

Or take crime. Here the public pressure for increased federal, state and local action is enormous. From Massachusetts to California, crime-related voter initiatives will be on the ballot in November. In legislature after legislature, support for punitive, retributionist legislation -- so-called "populist justice" -- is growing. The National Sheriffs' Association says that vigilante groups have doubled over the last 18 months and can now be found in 20,000 communities, in every state. There is every likelihood that this harsh mood will last most of the decade, especially if hard times lead to more urban violence.

Then there's national defense. Most Americans favor a stronger U.S. military posture vis-Ma-vis the Russians. Nationalism is exerting a considerable psychological force here and elsewhere in the world. But the history of defense buildups is that they almost always go hand in hand with an extension, not a reduction, in government power.

Two other continuing trends -- the surge of participatory democracy (state and local initiatives and referenda) and the erosion of existing political institutions by and in favor of communications technology -- are also indirectly collusive in the same direction. Participatory democracy is a close cousin of populism, and tax revolts notwithstanding, the historical thrust of populism is towards more government intervention in both the economy and moral issues.

The impact of new communications technology is harder to predict. Some say it will fragment power; history, however, suggests a correlation between communications advances and wider-reaching government. You can start with Gutenberg's printing press, trace the evolution through the impact of the telegraph on the revolutions of 1848, and wind up with Hitler and FDR on the radio. Pondering the future, the opportunity for Caesarism through television is enormous.

Obviously, all this isn't "conservatism." But it also isn't liberalism -- not with national industrial plans, crackdowns on crime, defense mobilizations and plebiscitary democracy. Which brings me back to post- conservatism and its corollary: that many of the most volatile political constituencies of the last 20 years -- the bulk of them Reagan backers in 1980, but now souring -- are looking for an odd mix of populism, patriotism, social traditionalism and economic interventionism.

At this point, the public's vague policy preferences -- to say nothing of any response by the Republicans, Democrats, Andersonites, New Right et al -- lack concrete form. To some extent, the existing forces would probably pull the policymaking of any U.of somS. government -- Ronald Reagan's Edward Kennedy's, George Bush's or Fritz Mondale's. Yet I can't help but think the forces I've described, if they continue, have a basically right-populist thrust.

If the Reagan administration persists in playing Coolidge Restoration games, the probable failure could either give the Democrats another chance or create an even more chaotic situation. Interestingly, MIT political scientist Walter Dean Burnham now suggests that the system could be heading for a breakdown. Possibly so. A good case can be made that neither party -- and neither party's philosophies -- can handle contemporary America's problems.

But it's also intriguing to weigh the possibility of Reagan tilting more toward more active government intervention. As of today, traditional conservatives in the Reagan constiuency would resist any trend toward increased statism; indeed, they condemn it as emerging more on the Democratic side. Yet there is also a potential amenability on the GOP side.

One of the few points where the chief executives of the Fortune 500 and New Right godfather Richard Viguerie overlap is that they both supported corporatist John Connally, not Ronald Reagan, for president in 1980. Much of the New Right electorate is a populist, post-conservative element that could be mobilized with a mix of patriotism, cultural traditionalism and economic activism. It's laissez-faire that offends their Andrew Jackson-George Wallace sensitivities, not government economic intervention. Adam Smith is not a big name in Opelika, Ala., or South Boston.

Traditional conservatives skeptical that the New Right could shift toward increased corporatism may be correct. But they should bear in mind the New Deal enthusiasm of these constituencies 40 years ago and the considerable evidence that radicalized middle- class electorates have moved in this direction before.

It's hard to predict the course of American politics over the remainder of the decade. There's too much institutional volatility. And it's hard to predict how Ronald Reagan will resolve his mid-term crisis. The one thing that does seem clear is the limited utility of the passive doctrines of Calvin Coolidge. In the 1980s, as in other decades of crisis, the American people will follow the politics of activism -- for better or worse.