Sen. Gary Hart (D-Colo.), in his political coming-out speech of 1985, today called for a "true patriotism" based on "excellence, justice and community" and denounced President Reagan and the Republican Party for "hollow promises" and "patriotism consisting merely of nationalistic flag-waving, public relations symbolism and military interventionism."

Fresh from a tour of Europe and the Soviet Union, Hart's noontime speech to several hundred supporters at historic Faneuil Hall, had the look and feel of presidential politics in its infancy.

From the small motorcade to the trail of photographers, from the live shots on the local noon television news shows to the introduction by former senator Paul E. Tsongas (D-Mass.) calling Hart the frontrunner in the 1988 Democratic presidential sweepstakes, there was little attempt to disguise Hart's reentry into the political scene. Hart said he would make no decisions about his future until the end of this year.

Today's speech was broad and thematic. It was, said the runnerup to Walter F. Mondale for the Democratic nomination last year, the beginning of an effort to "recapture" the traditional American symbols that he said the Republicans have taken away from the Democratic Party -- and also an effort to mold his party more in his image.

"Traditional liberalism protected and preserved our national values for more than 50 years," Hart said. "Now to advance those same values, we must accept change. Our past achievements are not a cathedral in which to worship but a firm foundation upon which to build a new vision . . . . The party of change must change."

The closest Hart came to a new proposal was his call for "a new system of national service" -- military or otherwise -- for America's young people.

He was most topical when he declared, "Candidates for election, and appointment, to high office must once again have ethical standards based upon the highest -- not the lowest -- common denominator. And that includes . . . the attorney general of the United States."

That, he said later, was an acknowledgement that he intends to vote against confirmation of Attorney General-designate Edwin Meese III.

But mostly, he concentrated on laying out a general framework for the country's future. Hart attacked the "Darwinism-with-a-smile" of the GOP, saying "the Republican right-wing speaks the language of our values while acting against them."

Instead, he urged the nation to follow a different course during this "era of profound transition," what he called "a vision flowing from our natural idealism and calling upon a genuine patriotism."

"Genuine patriotism must appeal to the deep sense in all of us that each of us can do better at our chosen tasks, that our nation can do better at home and abroad, that there is a higher purpose for a great nation than outdated political arrangements on the one hand, or self-interest, materialism and selfishness on the other," he said.

For the Democratic Party, that requires a departure from the old order."

"As its own standard of excellence, the Democratic Party must now weigh all its policies against the standard of the national interest," Hart said. "The Democratic Party must govern well, but it must not be the party of government. Democrats must understand that government exists to serve the people and not the people to serve the government. . . . Demands of special interest groups -- including the party's own constituencies -- should be important but secondary."

Hart drew some of his strongest applause in reciting familiar Democratic Party ideas: women's rights, a clean environment and an end to the arms race. He called for a "moral rededication to civil rights, equal rights and equal opportunity, through social action, legal protection and a new economic agenda."

Hart called for the reestablishment of a sense of community in America and said "commonplace courage," in the home and school, in the factory and boardroom, is the thread that could stitch the nation back together.

Tsongas, who recently retired from the Senate, gave Hart the kind of introduction a potential candidate for president could only dream of three years before the 1988 contests.

"Make no mistake about it," Tsongas said. "He is the leading Democratic candidate for the nomination in 1988 . . . . In time we will be able to say we were here the day when he enunciated the new platform for 1988 that took him to the White House."