What can the nation's cities, home to many of America's minorities and hard-core unemployed, do to defend their residents' interests in this era of heavy cutbacks in federal social and manpower programs?

One promising survival strategy is taking shape here in Boston, which anticipates a phenomenal $10 billion wave of office building, hotel and commercial construction during the 1980s. The idea -- easily transferable to scores of other cities now enjoying downtown building booms -- is to use the power the city wields to implement a "resident-jobs programs."

Under the Boston plan, 50 percent of the construction jobs and 50 percent of the permanent jobs in city-aided projects must go to people who live within the city limits. And that includes not just city-financed buildings, but all other projects over which city hall has special leverage -- those built with federal subsidies, those enjoying property tax relief, factories or warehuse in city-run industrial parks, perhaps even even projects that only need a city zoning variance.

You can call it a raw exercise of political power, and that is precisely what is is: a way to "leverage" the vast investments flowing into downtowns so that hard-pressed city residents, and not just private investors, enjoy the benefits. Variants of the Boston plan are being introduced in other cities -- among them Dayton, Ohio; St. Paul, Minn.; Cambridge, Mass.; and Wilmington, Del. Many of these aren't precisely resident plans but do require that 10 percent or more of new employes be persons eligible for Comprehensive Employment and Training Act programs.

The Boston plan, the most advanced to date, was conceived by a miniorty workers' training and referral group and embraced by Mayor Kevin White during his 1979 reelection campaign, when he faced a formidable black opponent. Politically, it was a "win-win" situation for White, since the potential gainers included Boston's large white ethnic groups as well as blacks and Hispanics. During the '70s, up to 80 percent of the construction workers on Boston jobs were suburbanites -- with rarely a minority person among them.

There's now some doubt about White's total commitment to the policy. He currently is diverted by a colossal crisis over implementation of Massachusetts' controversial 1980 tax-cutting initiative, "Proposition 2 1/2." And he may be reticent to engage in a knock-down fight with the construction trade unions, notoroius for their discriminatory membership practices but still a potent force.

But White's policy does have the force of an executive order. And it not only sets aside half of construction jobs for city residents but mandates that a quarter of all jobs at all skill levels go to minorities. Thus the minority job slots can't be shunted off to simple laborer jobs while white workers totally monopolize the higher-skilled and higher-paid jobs such as iron workers and electricians.

A key test will come this year as construction moves into full gear on the massive $350 million hotel-office-commercial Copley Place project, which will employ 1,200 construction workers over three years. In return for helping to get a $18.5 million federal UDAG (urban development action grant), the Copley Place developers -- the Chicago-based Urban Industrial Development Corp. -- signed legally enforceable agreements on minority and city-resident construction-worker quotas. The developers also agreed to encourage their tenants, who will hire a projected 6,600 permanent workers at Copley Place, to follow the resident-jobs policy.

There's great promise in such construction-worker goals, says John Lornager of the Hartford (Conn.) Policy Center, which has been studying the resident-jobs policy in Boston and other cities under a federal grant. But the 50 percent requirement for permanent employes of a manufacturer or low-skilled hotel workforce, he notes, may not be "worth a hill of beans" since such employers usually draw over half their workers from city residents anyway.

Still, Loranger believes, the agreements may have a huge side benefit: to give a city's manpower agency advance notice of employers' plans so that they'll know months or years ahead of time just what categories of jobs will be opening up. A manpower agency thus will have time to recruit and train CETA-eligible workers, women, and minorities, "creating the linkage that has never existed before between the training of those individuals and the jobs at the end of the line." That puts a heavy onus on city manpower agencies -- often the weak sisters in urban governments -- to act aggressively and efficiently.

But Kirk Sharfenberg of The Boston Globe, while noting such problems, argues out that 50 percent requirements aren't grossly discriminatory if they still permit half the workers to come from outside the city's borders. Resident-jobs policies, he believes, can reassure often embittered working-class youth that there really are likely to be jobs for them.

All that is true. But the most exciting breakthrough of resident-jobs policies may be the power they give our cities to act forthrightly in the defense of their own people.