"I will build a motor car for the great multitude." That's the promise that made Henry Ford a national hero. In 1914, his offer of $5 pay for eight hours work made Detroit a magnet for what historian Nelson Lichtenshein calls "a `suitcase brigade' of displaced European peasants, underpaid farmhands and unemployed coal miners."

Many were disappointed. Ford's $5 daily wage, for example, was tied to backbreaking piecework schedules and home visits by Ford inspectors who asked, among other things, how often workers bathed. By the 1930s, dozens of Americans were dying each year in picket line violence. Millions were so skeptical about capitalism that labor radicals and New Deal reformers had a decisive impact.

One of those radicals was Walter Reuther, whose lifelong dream was to make the link between mass production and mass consumption a permanent feature of American life. He pushed a string of U.S. presidents to pump up economic demand. He struck General Motors Corp. for 113 days in 1946, demanding a 30% wage boost with no increase in car prices. "Unless we get a more realistic distribution of America's wealth," he told GM bargainers, "we won't get enough to keep this machine going." GM was horrified. It threw its weight behind the Taft-Hartley Act of 1947, and other measures, that weakened labor's clout.

Mr. Reuther led millions of Americans to decent wages, safer workplaces and the rudimentary tools of workplace democracy. By the time he died in a plane crash in 1970, however, he knew his dreams were fading. He'd seen thousands of his members swayed by the racist appeals of Alabama Gov. and Presidential aspirant George Wallace. He'd seen wages and productivity and overall economic growth stagnate, in part because overseas competition was intensifying. He'd seen hundreds of Midwest companies follow Interstate highways south to weak unions and low wages.

Between 1979 and today, UAW membership has been halved to below 700,000. Instead of representing one in three private-sector workers, as they did in Mr. Reuther's heyday, U.S. unions now represent just 1 in 10. Over the same period, annual income for the poorest fifth of U.S. households dropped 3% to $7,800. Incomes for the richest 5% of households jumped 40%, to $183,000.

This income gap is hurting Detroit. In 1979, it took 23 weeks of income for the average family to buy a new car; in 1995, it took 30 weeks. In 1980, the richest fifth of U.S. households bought 40% of new cars; today, the richest fifth buy 55%. As Detroit's market becomes more elite, it becomes smaller. In 1996, U.S. car and truck sales will total somewhat over 15 million; the 1986 peak of 16.3 million vehicles may have been the industry's high-water mark.

Most Americans, however, have not turned to unions as the answer. To some, that's another sign that U.S. unions are evaporating.

Certainly, the unions have been slow to find their way in an increasingly globalized and digitalized economy. They've failed to organize most of the hundreds of non-union auto assembly and parts factories that Japanese and German automakers have opened from southern Ohio to Alabama. They've failed to win support for activist government. New York Times Columnist William Safire says it's "socialism" pure and simple for President Clinton to propose using the tax code to encourage employers to spend money on jobs and high wages, not only new plants and equipment.

If the political mood doesn't shift, U.S. unions will continue to decline and will become more like unions in Japan, says Steve Babson, a researcher at Wayne State University in Detroit. That would mean as much as half of autoworkers' pay would be contingent on performance evaluations, he says. Shop-floor work teams would lose much of their autonomy, thereby limiting their ability to boost worker morale and cut turnover. As much as half of routine final assembly work would be contracted out, as at Toyota in Japan, meaning the automakers would be mostly financing and marketing organizations.

It's too soon, however, to write the obituary of U.S. unions. Just-in-time inventory systems mean that inside Big Three factories, "the UAW is more powerful today than it's ever been in history because we maintain the power to shut down plants," says Doug Fraser, one of the UAW's most colorful retired presidents. UAW leaders clearly are willing to use this power in controlled ways, as their recent strike at two GM brake plants in Dayton, OH, clearly demonstrate.

Further, continued deunionization runs counter to history. Unions exist in all Western democracies. They are a significant, if repressed, force as countries such as South Africa and South Korea leap from colonialism and poverty to independence and prosperity.

Dan Luria, a former UAW staffer who's now with the Industrial Technology Institute in Ann Arbor, MI, rates the chances of catastrophic deunionization in the United States over the next decade as 2 in 10; of industrial union decline offset by public union growth as 7 in 10; and of a 1930s-style union upsurge as 1 in 10.

Nobody can choose their destiny. Here, however, are key features of what unions themselves are doing to survive:

* Bargaining. Outsourcing will be the core issue in UAW contract talks this fall. Compromises are not impossible. The UAW may accept flatter wages at parts plants, argues a GM executive if newley-hired parts workers could eventually transfer to assembly, powertrain or stamping plants, thus qualifying for full wages.

* Union reform. Stephen Yokich, the UAW president, helped elect John Sweeney as president of the AFL-CIO. While he was at the Service Employees International Union, Mr. Sweeney championed radical tactics, like blocking Washington, DC, bridges to boost organizing drives among janitors.

Mr. Yokich also is spearheading "Big Metal," that is, the merger of the UAW, the steelworkers and the machinists. By the year 2000, "Big Metal" will include 2 million members and will resemble IG Metall, the vast union of German metalworkers. UAW leaders believe they lost the Caterpillar strike last year because they allowed the company, during a period of labor-management detente in the 1980s, to shift critical component jobs to outside factories. One of those is an Illinois factory where workers of the machinists union kept working during the UAW strike. The merger, presumably, will make such a debacle less likely.

* Organizing. Workers don't join unions, a presidential commission concludes, in large part because illegal discharges occur in one of three organizing drives. The SEIU is managing to grow, despite these discharges, by spending 30% of its budget on organizing. That's 10 times as much as the UAW.

A high-level UAW task force is now completing a plan to boost organizing. Mr. Lichtenstein, the historian, thinks "the next great frontier" for the UAW is Big Three white-collar workers now viewed as expendable. Additional possibilities: going after suppliers such as Bosch GmbH or Dana Corp. in several locations simultaneously, instead of one plant at a time. Another possibility is regional organizing of, say, all parts workers in southern Ohio. That's how IG Metall runs its organizing campaigns.

* International solidarity. One of the "dirty little secrets" of the Caterpillar debacle (strike and lockout) in 1994-'95, says one UAW official, was the lack of effective support among unions in Japan, Belgium, France and South Africa. George Kourpias, the machinist president who now runs the AFL-CIO's international affairs staff, is shaking things up. Among other things, he's thinking of selling a $900,000 Paris apartment from which, for decades, AFL-CIO operatives met with the Central Intelligence Agency and others to plan anti-Communist crusades. "Now that the Berlin Wall has fallen," the UAW official says, "the AFL-CIO's international affairs staff has little choice but to confront capitalism."

* Politics. At the AFL-CIO, Mr. Sweeney has mandated a seven-fold increase in spending on political campaigns. He has targeted 75 U.S. congressional districts in hopes of limiting or even eliminating the Republican majority this fall. If he succeeds, U.S. unions will emerge as the anchor of U.S. liberalism, and the prime critic of widening U.S. income gaps, for the first time since Walter Reuther's death.