Ronald Reagan's reelection victory was the latest act in a long-playing American political drama, ''As the Realignment Turns.'' After each election commentators ask, ''Has the play opened?'' - that is, did we see at least the beginning of a partisan realignment? In fact, the play opened a long time ago.
If one wants to locate the time of the curtain raiser, and the place, it almost has to be 1948 in the American South. White Southerners had been the strongest link in the New Deal coalition, and indeed the most loyal supporters of the Democratic Party since the Civil War. In 1948, however, they began their long march away from the Democrats. The States' Rights Party of Strom Thurmond seized on white racial protest against Truman policies and carried four Southern states. Democrat Harry Truman won the support of just 53 percent of white Southerners. In subsequent elections over the 1950s and '60s, opposition to the national Democrats' racial policies was combined with the increasing attraction that an industrializing and newly prosperous South felt for the Republicans - producing a swing to the GOP presidentially. Jimmy Carter, the first Southerner to be nominated for president by a major party since the Civil War, and clearly the beneficiary of substantial regional loyalties, was nonetheless unable to win a majority of the vote among Southern whites in 1976, and he got only about one-third of this vote in his losing effort against Ronald Reagan in 1980. The same group went 85 percent for Franklin D. Roosevelt in 1936 and just 20 to 25 percent for Walter Mondale in 1984.
Over the last three decades a number of other groups that had been mainstays of the New Deal coalition swung gradually to the Republicans. Although labor unions went all out for Mondale this year, the blue-collar vote went for Reagan and the union vote (that is, voters from households where at least one adult was a union member) gave Mondale a modest margin. Roman Catholics have swung from their historic attachment to the Democrat Party, and they gave Reagan a clear majority this year. These and other important shifts have not been wholly uninfluenced by Mr. Reagan's personal popularity, but they antedate the Reagan presidency by many years and result from deep-rooted social changes.
The big act in the realignment drama of the 1970s involved a movement away from the Democrats on questions of political economy - the role of government in national economic affairs. Since the New Deal, the Democrats had held to their standing as the ''party of prosperity.'' But in the 1970s they lost that reputation, so far as majority views are concerned, under the dual challenge of high inflation (seen as government's fault) and frustration over the extent of government's growth. A national majority did not decide in the 1970s, however, that the Republicans were better on economic issues - only that the Democrats' approach left much to be desired.
It has been a major achievement of the Reagan presidency to carry these perceptions of the parties and the political economy one step further: The Democrats' approach still draws criticism, but now the Republicans' approach receives a more positive, if tentative, endorsement. This accounts for the public's responses in a CBS News/New York Times poll a month ago to the question ''Which party is better able to insure a strong economy?'' Nationally, 54 percent said the Republicans, only 27 percent the Democrats.
Big changes affecting the interests of key social groups began eroding the base of the New Deal coalitions long ago. In the last 15 years, a new political economy has weakened the Democrats' position in presidential voting. Add to these factors the personal popularity of Reagan. More than bringing in additional votes, his appeal provides a bridge over which blocks of voters, especially young people, might be induced to cross toward more regular Republican support. The latest acts of our drama have displayed an internal tension perplexing to many viewers. What is one to make of a realignment so incomplete that the GOP dominates in presidential contests but remains decisively in second place in voting below the presidential level? Reagan aspires to the role of FDR - whose personal standing helped enlarge and extend Democratic support in the 1930s.
In percentage terms Mr. Reagan's margin in 1984 falls slightly below Mr. Nixon's in 1972 and Mr. Johnson's in 1964. But Johnson and Nixon were running against candidates who were out of the mainstream of their respective parties. In contrast, Reagan confronted a centrist Democrat of ability and experience, who ran an energetic and intelligent campaign, and who was backed by the leaders of every major group in his party's historic alignment. Reagan's margin over Mondale of 18 percentage points was, then, notably impressive.
Still, the key factor in our long-playing realignment drama will likely be written not by Mr. Reagan's personal appeal, but by the public's perception of Republican performance in serving the social and economic well-being of the entire populace. Will the GOP's approach ultimately be seen as successful, not merely promising? Or will it crash against deepening economic problems and social conflict? In the last analysis American voters are performance-oriented, as they have always been. A deeper, broader Republican majority will only come the old-fashioned way - the GOP will have to earn it.