As in many things, the history of American social legislation may provide an indicator of the future.

The 1935 Social Security Act, which led the states to create unemployment insurance programs, drew key elements from an unemployment program enacted in Wisconsin three years earlier.

The 1965 Medicaid health program for the poor was a lineal descendent of programs in which the states, with federal aid, made "vendor payments" to providers of medical care for state welfare recipients.

The 1972 Supplemental Security Income program, under which the federal government assumed basic responsibility to support the nation's destitute aged, blind and disabled, grew directly out of federal-state welfare programs for these groups, which in turn had been built upon state-only programs.

Today, the central issue in social welfare policy is how to provide health care for 31 million Americans who lack health insurance from either private or government sources. And as in the past, states are moving forward on their own to tackle such problems.

A block of state legislators from 11 states, including Maryland Sen. Paula C. Hollinger (D-Baltimore County) and Virginia Sen. Stanley C. Walker (D-Norfolk), has just formed a State Alliance for Universal Health Care to push state action on health care. The National Governors Association will hold a conference here Sept. 23-24 to discuss health care costs.

Even as many states, because of costs, are resisting new federal moves to force them to expand Medicaid, many are experimenting with various forms of health legislation. This activity is being spurred by lobbying coalitions of labor-liberal groups such as Citizen Action, and unions like the American Federation of State, County and Municipal Employees.

"We are pursuing these initiatives . . . because it is absolutely essential that citizens have better access to health care and that we have universal coverage," said Edwin Rothschild, an official of Citizen Action, which has 29 state organizations.

Gerald W. McEntee, president of the American Federation of State, County and Municipal Employees, said recently, "While AFSCME continues to pursue a federal program, we are increasingly concentrating our efforts on developing state alternatives."

Here is what some of the states have been doing, according to a research report from McEntee's union:

Hawaii for some years has had a system requiring employers to provide health insurance to their workers. It was made much more comprehensive last year.

Massachusetts and recently Oregon have set target dates for employers either to provide health insurance to their workers or to pay a tax that will provide the coverage -- the "pay or play" concept that was recommended on a national basis by the Pepper Commission headed by Sen. John D. Rockefeller IV (D-W.Va.).

Using grants, Arizona, Maine, Michigan, Tennessee, Wisconsin and West Virginia have set up demonstration projects under which small companies that cannot afford to pay insurance premiums are receiving subsidies to help them buy insurance.

In Washington state, the Basic Health Care Plan run by the state will subsidize insurance coverage for up to $30,000. In Minnesota, cigarette taxes were increased in 1987 to fund a health plan for low-income children under 9 who do not qualify for Medicaid; the age was increased to 18 on Jan. 1.

Connecticut, New Jersey, Maryland and New York created hospital rate-setting mechanisms that build into the hospital's charges a special margin to cover the costs of uncompensated care for the poor and uninsured.

New Hampshire, New Jersey, New York and Rhode Island have programs to cover some of the high costs of catastrophic illness.

Twenty-three states operate "risk pools" that, in effect, allow some people considered medically too risky to be sold commercial insurance to buy into a health insurance plan at high, but not prohibitive, prices. Premiums are usually 25 percent to 50 percent higher than for private insurance, and purchasers are usually people with circulatory and heart disease, cancer and diabetes. About 50,000 people are covered, and the plans usually operate at a loss, requiring large state subsidies.

The report said numerous states, including Ohio, Missouri and Illinois, are considering health insurance plans. Washington state has under consideration a large expansion of its Basic Health Care Plan into a universal comprehensive plan for everybody in the state.

Whether the effort to get states to act will eventually lead to adoption of a comprehensive national health system is not clear. Some national health insurance advocates, who asked not to be identified, worry that it will take away the pressure on the federal government to adopt a comprehensive plan.

But Citizen Action's Rothschild does not share this view. "We need to have a federal system," he said, "and we know from past experience that the federal government only moves after the states start the process."