Now that Ronald Reagan has been elected president of the United States, it is possible to look both backward and forward to the golden summer of '81. The feeling of euphoria following Reagan's triumph has an oddly nostalgic, tone, as if the future already has come and gone. The doubling effect produces a sense of heightened rapture among Reagan's various constituencies, an exhilaration reflected not only in the optimism of the stock markets but also in the joyful thanksgiving of Christian generals and the counting out of the coins of patronage among Republican politicians.

When the Democrats seize the White House, they arrive in Washington amidst the loud cries of promised achievement; the Republicans tend to think of a world less encumbered with nuisances. Through the patriotic haze of Reagan's campaign rhetoric, his admirers envision the summer of '81 as both Utopia and the lost Eden, a green and happy landscape distinguished by the following landmarks:

OPEC -- Nothing more than an unpleasant memory. By dismantling the Department of Energy and rescuing the domestic oil and gas reserve from the dungeon of federal regulation, Reagan restored the United States to its accustomed profigacy. The Arab cartel packed up its tents and vanished silently into the desert.

The Persian Gulf -- An American lake. The U.S. Navy stations a flotilla of gunboats in the Strait of Hormuz. The grateful Moslems wait for American sailors to come among them on shore leave, distributing the traditional gifts of transistor radios, gonorrhea and baseball caps.

The Russians -- Cowed. Having looked into the granite faces of Reagan's warlike professors, the Russians abandoned the arms race as a futile pretension. The members of the Politburo know themselves to be the custodians of a second-rate military establishment and a failed ideology. Andrei Gromyko devotes his attention to the ballet.

Latin America -- Safely in the hands of dictators and brigadier generals. As a concession to the beauty of human rights, a Latin American poet or novelist annually receives a Nobel Prize.

China -- The principal market for large American automobiles.

The Third World -- Beginning to understand that its problems are its own damn faulty.

The dollar -- Backed by gold and therefore impregnable against the speculation of foreigners.

God -- Returned to the public schools, instructing the nation's youth in its civic as well as its Christian duty.

Blacks -- Self-effacing. Except for the professional athletes among them (who earn upward of $250,000 per annum and thus prove the validity of the capitalist ideal), the blacks have retired into a decent obsurity. Once again it is safe to go to nightclubs in Harlem.

Taxes -- Token payments of conscience, as easy to bear as the occasional gifts bestowed on universities and museums.

Children -- Obedient. College students appreciate the value of a steady job.

Fornication -- No longer conducted in public. Mindful of the laws against abortion, only pregnant women of impeccable marital status venture into the streets.

The poor -- Off the government's back. The more deserving among them work at menial jobs in order to send their children through Cornell.

Washington -- A deserted boom town. Where there were great fortunes to be made in the diggings along the Potomac, the town attracted the gang of thieves that traditionally debauches the morals of a gold camp. Reagan's election proved that the mines had been played out, and the carnival of whores and confidence men drifted south or died of drink. The decent citizens who remain tend quietly to the building of churches and the development of nuclear weapons.

The press -- Content with routine catastrophes. The State Department still provides two or three minor wars to coincide with the opening of the season at the Kennedy Center. The possibility of scandal in the defense or justice departments occupies those reporters not assigned to investigate the rumor that a Cabinet officer's wife has been introducing Foxcroft girls into the white slave trade.