MIAMI BEACH--Party leaders and delegates to the Republican National Convention spent many uncertain moments have last month reminding themselves that there was, in fact, a reason for their being in Miami Beach.

It was billed as a nominating convention. Instead, Miami Beach Convention Hall was transformed into a huge studio in which the Republicans unsheathed their 1972 campaign strategy and paid tribute to their incumbent President before a prime-time television audience.

The delegates were merely actors in the unsuspenseful drams. Three thousand Young Voters for the President played a crucial supporting role. The powerful elite which steers the Republican Party spent four days directing producing and orchestrating the gala event--gala, this is, if the proper credentials and invitations to lavish afterhours parties were obtainable.

For most people, those credentials and invitations were well out of reach. In Flamingo Park, 4500 uninvited and unaccredited non-delegates--mostly young--plotted to disrupt and embarrass the Republicans. They sought to confront President Nixon once more over his policies of Vietnamization negotiated settlement and bombing in Vietnam.

But even the protesters were swept under by the supra-efficient planning which fused the Republican's gathering in Miami Beach. Their goal of forcing the President to deliver his acceptance speech before a half filled auditorium seemed an improbable one at the outset; its chances for success diminished steadily as internal dissension over tactics of violence and non-violence split the demonstrators.

Then, too, there were the police who had stood by in ponderous numbers for the Democratic Convention only six weeks earlier. Their ability to strike quickly and effectively had not diminished; during the final two days of the Republican Convention, they arrested over 1400 persons, dutifully photographing and booking each one and advising them of their rights. The streets outside Convention Hall were thick with crowd-control gas, but inside, Richard Nixon addressed an overflow audience which embraced him with unabashed warmth.

It could not have gone better for the Republicans, even the street disturbances which injected a smattering of spontaneity into an otherwise preordained scenario. For three days, Republican leaders had been praising Richard Nixon as a man of warmth, moderation and sensibility. They had called out to discontent Democrats to join the Nixon bandwagon. Most of all, they had created a strained comparison between the clean-cut, exuberant, All-American kids tagged Young Voters for the President and the long-haired, dungareed McGovernites who had filled Miami Beach six weeks before.

The logical extension of this comparison was that the protesters in Flamingo Park were also McGovernites. So it was that the trouble on the streets fit perfectly into the scheme, complimenting the written script which timed every demonstration, every burst of applause, every "spontaneous" resolution from the floor inside Convention Hall. The delegates made it inside with a minimum of obstruction, the cameras were focused on the President as he again accepted the nomination of his party, and outside, as the media would dutifully report afterwards, police were sweeping 1200 unruly demonstrators of the radical left into Miami's jails.

Those who witnessed the Republican Convention last month came away with a taste of tactical politics extraordinaire. The Republican were impressive not for their departure from tradition, as the Democrats had been in July, but for their adherence to the strictest guidelines of party politics. They sought to reinforce an already wide lead in Presidential polls, to coalesce unlikely allies into an unbeatable force designed to propel Richard Nixon back to the White House with something he has never won in a Presidential race--the vote of the majority.

The scripted deification of President Nixon reflected the political acumen of men like Senator Robert Dole (R-Ken), the chairman of the Republican National Committee, and Clark MacGregor, John Mitchell's successor as head of the Committee to Reelect the President. It pivoted on the tremendous funds which these men have at their disposal. A $44,000 podium designed for maximum television exposure, the most sophisticated electronics ever employed at a political convention, a series of documentary films highlighting the President, his family and his party--it was a staggering example of what money can buy and of how well-financed media presentations can influence the electorate. Moreover, it was an amplified revival of the strategy Joe McGinniss' described in his book on Nixon's 1968 foray. "The Selling of the President."

The five sessions of the Republican Convention were conceived as the initial thrust of a coalition campaign. Timed to the split second, the Convention worked around several themes bringing in Democratic centrists and conservatives by appealing to bygone days of unity, stalking the youth vote previously conceded to Senator George McGovern, and mounting a fear of what McGovern might do if elected President.

So it was that Senator Barry Goldwater (R-Ariz), the conservative Republican nominee of 1964 who suffered the worst defeat in electoral history, was shifted out of prime time because he refused to tone down a speech attacking not just McGovern, but the Democratic Party. While he waited in the wings, the name of his opponent. Lyndon B. Johnson, drifted through Convention Hall along with those of other prominent Democrats, ranging from Franklin D. Roosevelt to Harry Truman to Richard Daley. And much like expatriates paraded before the Old Country's press. Democrat after Democrat was brought forth to confess conscience-rending decisions to cross party lines and support the President. George McGovern was just too radical. Two Democrats for Nixon were even included among 11 seconds following the President's renomination speech by another old foe,' Gov. Nelson Rockefeller of New York.

The singlemindedness among Republicans of every persuasion was the mark of the 1972 Convention. After 12 years of frustration, they hold a position of strength sufficient to cause astute political observers--including James Reston, the foremost observer--to devote thought to the prospect that the Republican Party could become the dominant, if not majority, party after November. The Republicans sought to seize the moment and exploit it to the utmost. Somehow, though their efforts came across only as exploitation. They lacked the genuine touch which permeated Miami Beach during the Democratic Convention. And whether they really do seek progress or not--a question left unsettled by their Convention behavior--the Republicans have backed into a campaign which will pit the slick media front born of big money against the grass-roots tactics of a hazily-etched, emerging political camp.

Comparisons between the Republican and Democratic Conventions are inevitable because the differences between the two crystallize November's election choice. It is unfair to pan the Republicans for the absolute control and staging which distinguished their gathering, on for their blatant appeals to dissident Democrats. Shrewd politics win elections, and the two sure precedents for the Republicans' tactics are found in Democratic campaigns. Franklin Roosevelt exercised broad control over the 1936 convention which renominated him, and Lyndon Johnson did likewise in 1964. The Republicans of 1972 departed from these Democratic forerunners, though, because they were not confronted with immediate crises. Roosevelt guided a country steeped in depression. Johnson sought to reunify a nation still reeling from the assassination of John F. Kennedy less than a year earlier. But these Republicans in Miami Beach aimed only at buttressing a partisan bid for continued dominance--not just in 1972, but for years beyond. And in this effort, they resorted to the canned ballyhooing and poorly disguised appeals of a party which consciously shifts its base to achieve parties goals. August 1972 does not hold fast when contrasted with the genuineness of Miami Beach in July 1972. It is instead a picture of superficiality and false initiatives.

The central theme of the Republican Convention was that it was the "Open Door" convention, a convention based not on quotas but on the justice of a proven political process. The President struck home in his acceptance speech: "You (the delegates) have demonstrated to the nation that we can have an open convention without "dividing Americans into quotas ... the way to end discrimination against some is not to begin discrimination against others."