The friendly reception for Ronald Reagan by this beleaguered city's angry steelworkers, causing Reagan aides to sigh in relief, points to what his campaign could have been had not caution prevailed.

"We were scared to death about the treatment the governor [Reagan] was going to get here," an adviser confided. In fact, workers at the Campbell Works of Jones and Laughlin Steel greeted Reagan with unusual warmth. A threatened wildcat strike protesting Reagan's appearance came to nothing; an anti-Reagan demonstration fizzled. Although aides had decided against a Reagan spedch to a potentially hostile audience, the men were so friendly that he gave one anyway. p

That confirmed the wisdom of sending Reagan into die-hard Democratic areas, such as Youngstown, which rivaled Georgia in 1976 support of Jimmy Carter. The appearance here was, therefore, a test. Had labor leaders disrupted his visit, Reagan's jumpy advisers might have been frightened into scheduling him only in safe Republican strongholds.

Even so, Reagan in Youngstown was essentially playing on President Carter's unpopularity. Coached by aides to avoid blunders, he hazarded no specific proposals -- not even his own tax cut program. No vision of a resurgent America was put before the workers, starved for hope and fearful of losing their jobs.

That a trip into erstwhile enemy territory was risked means the Reagan campaign is not sitting on a lead as did Thomas E. Dewey in 1948 and Richard M. Nixon in 1968. But hesitancy about coming to the steel mill and reluctance to take bold positions suggest no effort to build a new majority coalition.

Reagan's organized effort to penetrate rank-and-file union members did not begin until early September when Michael Balzano, a Nixon White House emissary to the labor movement, was brought aboard. Balzano's first mission: refute leaflets distributed by the AFL-CIO's Commission on Political Education (COPE) depicting Reagan as anti-labor.

Reagan immediately agreed to sign off on a labor policy statement that put him on record as opposing a national "right to work" law, opposing repeal of the minimum wage and Davis-Bacon labor law and opposing application of antitrust laws to labor unions. Millions of leaflets reporting those stands are being distributed.

Balzano next scheduled Reagan himself in areas of maximum blue-collar distress -- Youngstown, Pittsburgh, Steubenville, Ohio -- followed by the National Maritime Union convention in St. Louis. Youngstown worried Reagan aides most. Its United Steel Workers members are among the most radical in the nation.

Those fears were fanned when Harry Mayfield, the union's district director in Canton, started recruiting USW members to protest the Reagan visit. It was not clear whether they would be strikers threatening a wildcat strike to close the Campbell Works or just demonstrators. Reagan's high command decided to cross no picket line and court trouble by scheduling speech for the candidate.

But Mayfield could enlist no more than 100 well-behaved, sign-carrying protesters. Workers inside the factory shouted friendly greetings to Reagan. Random interviewing of then showed overwhelming hostility to Carter and surprising large numbers willing to desert Democratic loyalties for Reagan.

In an area where some 13,000 steelworkers have lost their jobs since August 1977, these men feel the antiquated Campbell Works may be next to close. "We're fed up and we're scared in this [Mahoning] valley," one middle-aged worker told us. "Why not give Reagan a chance?"

After Reagan's tour, hundreds of workers spontaneously followed him outside. He abandoned the no-speech decision to board a flatbed truck, speaking without loudspeaker or even bullhorn. Would he forget the misery of Youngstown if elected? "It will be an awful long time before I forget what I saw here," he responded, referring to decaying closed steel mills he toured that day.

The blame was Jimmy Carter's, Reagan stressed. When a worker shouted that Reagan looked "10 years younger" than the president, Reagan yelled back: "That's cause I don't have anything on my conscience like he does." But whereas Rep. Jack Kemp would have used tax reduction to conjure up a new world of growth and incentive, Reagan asked for "our chance" now that the Democrats "had their chance" and failed.

Reagan last spring might have been more venturesome, but take-no-chances is today's theme. "I think we've reached the point of no return for Carter," one senior Reagan staffer told us. That prophecy may prove accurate, but it scarcely justifies passivity in responding to the greatest Republican opportunity of a generation.