FROM 1966 TO 1988, Republican strategists developed sophisticated tactics to polarize the electorate, split the decaying New Deal coalition and establish a conservative majority in presidential elections. In his first 18 months in office, President Bush has steadily undermined these tactics in what amounts to a major gamble: The assumption that the demographics of national elections and the issues driving voters are evolving into new and profoundly different forms.

Some of Bush's conservative critics contend that this gamble is likely to backfire -- permitting a revival of liberalism and threatening to stall some of the right's more innovative proposals. For congressional Republicans, the shift is particularly worrisome. Bush may have confidence that an increasingly affluent and suburban electorate is inclined to support Republican presidential candidates without divisive political positioning. But House Republicans, a minority since 1954, have yet to benefit from the social, economic and demographic forces that have led to a realignment in presidential elections. In what could produce significant intraparty conflict between the White House and Capitol Hill, many frustrated House Republicans are clearly unwilling to abandon such "red meat" issues as federally financed homeoerotic art and flag burning.

Many House Republicans see themselves as having a vested interest in maintaining one of the central GOP strategies of the past generation. Developed under Presidents Nixon and Reagan, it focused on replacing classic Democratic divisions between economic "haves" and "have-nots" with a new set of divisions. These divisions lie between taxpayers and tax recipients, between proponents of special preferences for minorities and advocates of an essentially unmediated "meritocracy," between supporters of majoritarian traditional values surrounding work and family and supporters of a competing set of values concerned more with the rights of individuals and of often controversial minorities, including the poor and homosexuals. While rarely explicitly racial, these new dividing lines have in part coincided with other divisions in the larger society between whites and blacks.

In many respects, the Bush administration has put together an assault on those polarizing strategies. Bush brought to an abrupt halt what had been continued warfare between the Reagan administration and traditional civil-rights groups; he has invited leaders of gay and lesbian organizations to a White House bill-signing ceremony; Barbara Bush has sent a sympathetic letter to the head of Parents and Friends of Lesbians and Gays; the president has shown continued reluctance to "censor" the National Endowment for the Arts. Although Bush has maintained his anti-abortion stand, his political appointees at the Republican National Committee are actively encouraging candidates and local parties to adopt pro- or antiabortion stands at their own discretion.

All of this tolerance has provoked squirming on the right. Anxiety turned to panic among many of the architects of the Reagan revolution, however, when on June 26 Bush declared that the politics of deficit reduction "require. . . tax revenue increases."

"From libertarians to social conservatives, opposition to tax increases has been the one binding agent" holding the Republican-conservative coalition together, said Stuart Butler, director of domestic policy studies for the Heritage Foundation. "The great Satan is the threat of taxes as a way of expanding government."

"One of the things I'm learning, and a lot of Republicans are learning as they watch the budget summit and tax {issue} unfold, is that in politics, the political interests of the presidency do not always coincide exactly with the political interests of his party in the Congress," said Rep. Vin Weber (R-Minn.), one of the key strategists seeking to build a Republican House majority. "You have to have a wedge issue to beat an incumbent Democrat, and you have to have some kind of wedge issues in many open-seat districts."

Taxes have provided just such an issue. Popular resentment over rising tax burdens throughout the '60s and '70s created an opening for Republican portrayal of a voracious, coercive Democratic government in thrall to free-spending liberal elites, diverting large chunks of the paychecks of working men and women to finance mushrooming public expenditures for welfare, food stamps and affirmative action.

In terms of public strategy, the 1988 Bush campaign embodied -- almost in caricature -- all the themes and strategies developed over the years by the GOP right to divide and conquer Democrats and liberalism: black crime (Willie Horton); patriotism (the Pledge, the flag factory); abortion; and a general assault on the liberal rights revolution (the ACLU). The strategy not only worked on its target audience -- Los Angeles Times polls showed that the voters most moved by the Bush campaign themes were key segments of the white working and lower middle class -- but it endeared Bush to genuine ideological, often middle-class conservatives, among whom his credentials had not been strong.

But by 1992, Bush may no longer need to rely upon such racially tinged, culturally explosive social issues; he may be able to rely upon a more upscale, suburban electorate already leaning to the GOP, a growing body of voters that does not require red meat, an electorate inclined for other reasons to abandon Democratic candidates.

Underlying the recent ideological shifts of the Bush administration, however, are significant changes in the structure of the Republican electorate and in the demographics of the nation. Most important is the declining importance of white, urban, working-class voters -- the "Reagan Democrats" whose ballots were viewed as critical throughout the 1980s and in Bush's own victory in 1988.

If demographic trends continue, the 1992 election will in all likelihood be the first in the history of the nation in which suburbs cast an absolute majority of the vote, according to census data. From 1968 to 1988, the percentage of the total vote cast by suburban residents grew from 35.6 to 48.3, and the figures are virtually guaranteed to top 50 percent in 1992.

"The suburban middle and upper-middle class are now the heart and soul of the Republican Party," said John Morgan, a Republican demographer and voting analyst who has studied the 1988 results in detail. "You don't have to run well in the central cities to win the state now. What is dominating the states is the suburban counties."

Morgan points out that Bush did not run as well as Reagan in blue-collar ethnic Catholic areas; but even without Reagan's level of support among these once-solidly Democratic voters, Bush went on to victory with margins that "exceeded or were comparable" to Reagan's '84 margins in "almost all the more affluent suburban" sections in the South, Midwest and West.

"Republicans can carry the Floridas and Pennsylvanias of the country just out of the {high GOP margins in} suburban affluent areas," Morgan said, "and the rest of the state doesn't matter." It used to be that the size of the Democrats' margin in areas like Detroit, Cook County and New York's boroughs determined statewide results, making it essential for the GOP to break loose a significant percentage of white city voters. Now, Morgan argues, Democratic big-city margins are routinely cancelled out in presidential elections by suburban areas such as Orange County in California, DuPage County in Illinois and Macomb and Oakland counties in Michigan.

Political analyst Richard Scammon, in a recent article in The American Enterprise, examined voting patterns in the 63 counties producing at least 250,000 votes. "The data show that although the Democrats still dominate the inner cities, Republicans are now on equal footing in many major metropolitan areas due in large part to their new suburban muscle . . . . Politics will no longer be a city-versus-rural competition, but a complex, three-way rivalry involving declining central cities (mostly Democratic), fast-growing suburbs (strongly Republican) and stable rural areas (leaning Republican) . . . . Given these new patterns, Democratic presidential candidates face real problems in the three elections that remain in this century."

Frederick Steeper, a pollster for the RNC who does not fully subscribe to the suburban-advantage thesis, said there is a significant difference on the tax issue between more affluent suburbanites and less well-off white voters.

"The tax issue really carries with lower-middle-class white Democrats, the ones who make from $25,000 to $30,000 a year, and both the husband and wife have to work. The $75,000 yuppie Republicans, they can afford a tax increase and they can find ways to shelter their income."

At the same time, the administration appears to regard blacks as a more important constituency to the White House now that the significance of Reagan Democrats is waning Bush clearly wants to lessen the severe hostility of blacks to the GOP, and any move in this direction will function to moderate GOP policy and rhetoric. In contrast, for GOP House members seeking to build their numbers, Reagan Democrats remain a vital constituency.

While changing demographics may make it possible for Bush to moderate his stand on taxes, and to take positions signaling accommodation with the civil-rights and gay communities, a number of conservatives argue that Bush is coming dangerously close to facilitating a revival of liberalism.

"The Bush administration was born of the Reagan revolution," said Morton Blackwell, head of the conservative Leadership Institute. "He has now sold his birthright for a mess of pottage laced with cyanide."

Butler, of the Heritage Foundation, contends that once a Republican president takes the lid off taxes, he is very likely to lose control of the debate: As soon as raising taxes becomes an inevitability, then liberal Democrats are in a position to push redistributive policies and to focus on the declining rates paid by the most affluent over the past decade.

A number of Democrats are in 100-percent agreement. Rob Shapiro of the Democratic Progressive Policy Institute said Bush has undermined the ability of Republicans to use the "no new taxes" pledge as a form of symbolic communciation "that says to the working and middle class, 'We represent your economic interests.' . . . The debate is now open for the Democrats to move in and declare 'no new taxes for the middle class.' "

The dilemma this has created for some conservative Bush loyalists is reflected in the comments of James P. Pinkerton, deputy assistant to Bush for policy planning. Last April, Pinkerton was the talk of conservative circles because of a speech he gave to the Reason Foundation, a libertarian think-tank in Los Angeles, outlining what he called "The New Paradigm." It is a strategy to apply conservative principles to the problems of the nation's slums and to broad areas of domestic social concern through innovative application of market forces, decentralization and individual choice.

"The future growth of the Republican Party depends on our ability to address the voters' concerns about other important issues such as health, child care, education and pollution. The New Paradigm enables the GOP to move forward," Pinkerton said, "without going back to the Great Society of noble rhetoric and unintended consequences."

At the core of the thesis is the contention that "the president has kept his campaign promises of a kinder, gentler nation and no new taxes. Because of his policies, America stands on the horizon," Pinkerton declared last April. Last week, Pinkerton said, "Okay, that was what I argued in April, and what can I say? Time comes every so often to think anew. I have a philosphical aversion to a tax increase, but I support the president in making the best deal he can."

Thomas Edsall covers national politics for The Washington Post. His new book on race and politics will be published next spring.