VENICE -- The standstill economic summit is over. The tourists and pigeons have returned to St. Mark's Square. The weakened leaders of the industrialized democracies have returned home after signing a communique so vapid that some of those who drafted it fell fast asleep as it was being read.

Treasury Secretary James A. Baker III, no stranger to summits, proved especially inventive in trying to put a good face on a gathering that expected little and produced even less. He said the summit was a success because the leaders had not backed away from measures their finance ministers had agreed upon before coming to Venice.

Such a success. Baker deserves a "Guinness Book of World Records" notation for the greatest effort to retroactively set low expectations for an economic summit. Using Baker's yardstick, any summit that didn't start a trade war could be deemed worthwhile.

There was a special sense of sadness about this seventh summit of President Reagan, his last on European soil. Even Reagan's adversaries could hardly have taken comfort from his stumbling performance here, especially if they remembered the energy and wit with which he once approached international gatherings.

At his first summit in Canada seven years ago, Reagan stood for something and was not reluctant to speak out. He had the radical idea that summits ought to be private gatherings where democratic leaders spoke frankly to one another about their aims and aspirations.

Reagan, in his first venture on the world stage, had plenty to say. He did not conceal his concern about the Soviets. He argued passionately that slashing income taxes and squeezing domestic spending was the path to healthier economies and a better life.

What happened to the impressionable Reagan at this first summit was instructive, but in the wrong way. The leaders had agreed among themselves to keep their talks confidential and Reagan regaled them with his ready store of anecdotes. They found his stories charming but were appalled by his lack of sophistication and his economic ideas.

"They simply laughed at him," said a Reagan aide of those days. The response hurt Reagan's feelings. It also alerted his "spin doctors," who were worried that Reagan might be portrayed as a fool. Abandoning the ground rules of confidentiality, they proceeded to tell reporters that Reagan had made a positive impression on his counterparts.

Unfortunately for Reagan, the spin succeeded while the exchange of ideas failed. Except in meetings with British Prime Minister Margaret Thatcher, whom he trusts, Reagan retreated into his anecdotes. Economic summits became just another public relations exercise.

When world leaders last week tried to initiate serious discussions about Soviet leader Mikhail Gorbachev's motives, Reagan was no longer interested or energetic. He contented himself with reciting shopworn lines that had been written for him in a recent speech.

Reagan has only one more summit left to his presidency, and it will be back in Canada where he grandiosely described the 1981 gathering as "sunrise at Montebello." Now that it is twilight time for Reagan, he could perform a public service by asking his fellow leaders to reexamine the utility of economic summits in their present form.

Those of us in the news media might do some reexamining of our own. By accepting the claims of the spin merchants for Reagan and other leaders, we have helped to convert these international rituals into spectacles where posturing substitutes for thought.

Of what earthly use to busy leaders are these expensive and empty spectacles that advance no new ideas? Wouldn't it be better to have economic summits -- or other summits -- when a need arises rather than simply holding them because they are on the calendar?

When Reagan goes to Toronto next year he ought to raise the question of whether annual economic summits have outlived their usefulness. Those of us who have watched their deterioration and perhaps contributed to it ought to raise this question, too.

Reaganism of the Week: Asked at the beginning of the summit plenary session Tuesday why the political statement issued by the leaders didn't have more teeth in it, the president said, "We couldn't think of anybody to bite."