Probing the effect of public's opinion on public policy

Do your opinions carry any weight in Washington? Before you say ''no,'' consider the evidence. A team of researchers at the University of Chicago's National Opinion Research Center (NORC) has found that public opinion and national policy parallel each other more closely than many assume. This is particularly true, they find, for social issues where some of the most sizable opinion shifts have occurred.

They found, for instance, that the 1964 Civil Rights Act, guaranteeing blacks the right to be served in public places, was passed only after public support for it moved from 54 to 66 percent. And they note that the 1973 Supreme Court decision that upheld a woman's right to seek an abortion on demand during the first three months of pregnancy followed a 32 percent hike in public support for such a policy over a period of several years.

With the help of National Science Foundation money, political scientists Robert Shapiro and Benjamin Page have spent much of the last six years studying public-opinion surveys conducted between 1935 and 1979 and relevant policy moves on more than 300 major issues.

The two carefully avoid drawing any cause-and-effect conclusions. But they admit that the influence of public opinion on policy, in some eyes a test of the democratic ideal, often appears strong.

In general, according to Dr. Shapiro, an assistant professor at Columbia University, public opinion tends to be stable, moving only gradually in any direction. Primary-election choices tend to be a volatile exception. And during the Iranian hostage crisis and the Soviet invasion of Afghanistan, the percentage of Americans favoring an increase in defense spending took one of the sharpest upward jumps in one year of any issue.

Although public-opinion shifts on social issues have tended to be small and steady over the years, they often add up to a bigger cumulative change and have moved in a generally liberal direction, according to Dr. Shapiro. Only in the last few years, he says, has there been a movement back to a more conservative position on issues such as abortion and capital punishment. And he says it is not as extensive or strong as the shift has been to the left over many years.

But the majority view does not always sway legislators in true democratic fashion. The researchers found that in more than half the cases, policy did not change at all despite shifts in public opinion or it took off in an opposite direction.

During the 1970s, for instance, Congress made moves to adopt the metric system though public opinion was increasingly opposed to it. And during a four-year period in the 1950s when public support for economic rather than military aid to allies rose a strong 26 points to 81 percent, the proportion of economic assistance in total aid voted by Congress declined.

Noting that strong public support for gun control and prayer in the schools has had no discernible legislative results in Washington, Dr. Shapiro says that sometimes the policy response takes several tries.

As a case in point, he cites Congress's move to lower the voting age to 18 only long after public opinion favored such a move.

Political scientists have long classified policy moves at the state level as more specialized and particularly susceptible to control by special-interest groups. But the NORC researchers found that on certain emotional issues - including abortion, divorce laws, and gun control - that frequently appear in opinion polls, states are more likely than the national government to move in the same direction as majority opinion.