The great day is finally at hand. It was precisely 200 years ago that the Framers signed the Constitution, ''took cordial leave of one another'' and went on to immortality.

Their legacy has survived civil war and social turmoil of every sort. And one way to commemorate the durability of their work is to ask ourselves whether we, of this generation, could redo their work so well.

The answer, I think, is: Are you kidding?

Begin with the fact that the 55 participants -- including the dozen or so who really mattered, led by James Madison and James Wilson -- devoted an entire summer to the enterprise. And if you count Madison's diligent preparation, much more than a summer.

Like us, they had other cares. Washington, we know from his letters to the farm manager at Mount Vernon, worried about his carrot beds and whether his fruit trees were properly pruned. Yet they gave the Constitution their full attention.

There are persons of constitution-making caliber among us. (My list would include, for instance, Griffin Bell, Lloyd Cutler, Howard Baker, Lewis Powell, Daniel Patrick Moynihan, Derrick Bell.) But who among these busy figures could afford the time?

Even if we assembled a 1987 version of that ''gathering of demigods'' (Jefferson's characterization), attendance would be spotty. The competing distractions would require, as all public enterprises do nowadays, the formation of a staff of hundreds. (The original convention made do with a staff of one: Maj. William Jackson, its secretary.) And the staff would no doubt be mostly bright, green legal eagles with no great experience of affairs and not a thought about the fortunes of ancient and modern confederacies.

The second problem would be the endless importunings of single-minded fanatics and zealots of every sort, from ethnic and feminist lobbies to the military-industrial spoilsmen -- all taking out full-page ads to keep their demands in the public eye.

Not far behind them would come my beloved colleagues of the press, with their whirring cameras and glaring klieg lights and their demands for injunctions against closed meetings. Meeting in emergency session, the American Society of Newspaper Editors would demand ''the public's right to know.'' The New York Times would fulminate against ''secret covenants, secretly arrived at.''

And even if the convention managed nonetheless to keep the doors shut, an armada of reporters, with Sam Donaldson and Bob Woodward leading the pack, would fill the air and the newspapers with disruptive leaks and speculations.

No doubt the most damaging leak would concern the Osnaburgh Caper. For reasons no historian has ever exactly pinned down, rumors circulated that the Bishop of Osnaburgh, a younger son of George III, was to be named first king of the United States. There was a list of delegates said to be willing to establish a monarchy, and Dan Rather would surely have it on the evening news before the ink was dry.

Or maybe it would be a leaked and garbled account of Alexander Hamilton's stunning speech of June 18. Among other elitist desiderata, Hamilton called for lifetime senators and state governors appointed by Congress. Imagine the hysteria on ''Nightline''! America held hostage by 55 elitists! Soon there would be rioting in the streets.

But suppose, to imagine the unimaginable, that all these barriers were successfully hurtled. Even so, the convention would not, could not, withstand the massed fury of outraged piosity.

For among the immortal 55, there was not so much as a single parson or holy man or guru -- not one. No Falwell or Robertson or Billy Graham; no Paul Moore, no Archbishop O'Connor. And when it was divulged, as surely it would be, that the venerable Dr. Franklin's proposal for daily prayers had been summarily dismissed as an unnecessary expense, there would be hell to pay. Or heaven.

And supposing this ungodly and impious assemblage of rationalists and deists had actually completed the text and there was not a single mention of God or religion in it but for the exclusion of religious tests for office. Apoplexy! Fire and brimstone! Sodom and Gomorrah all over again!

Chanting ''Onward Christian Soldiers,'' the hosts of righteousness would march on Independence Hall. The reprobates would flee for safety through a rear exit, counting themselves lucky not to be struck down long before by a bolt of lightning.

And for the Constitution of 1987, that would be that.