THIS SUMMER, efforts have been launched to register more black and more Hispanic voters. Leaders of these efforts, such as Jesse Jackson, point out that if only a small percentage of black non-voters in, say, Alabama had voted, the 1980 election there would have come out the other way. That's true in dozens of cases, and not just because blacks cast about 90 percent of their votes for Democrats in most general elections. There is a very large pool of non-voters of every race, ethnic origin and description--enough to change the result of almost any election. In the 1982 congressional and state elections, about 63 percent of those eligible to vote did not do so. In the 1980 presidential election, 46 percent of those eligible didn't vote.

The large numbers not voting are all the more striking because voter turnout as a percentage of those eligible was in continuous decline from 1960 to 1980; yet during those years barriers to voting fell. The The Voting Rights Act of 1965 enfranchised millions of blacks in the South. In dozens of states laws were changed to make it easier to register and to vote. The period during which you had to live in a state before you could vote was reduced, by court decision, from as much as two years to 30 days. Yet for years fewer and fewer Americans bothered to vote.

Why? The baby boom generation is one answer (as it is to so many questions): young people who don't have roots in a community aren't very likely to vote, and the baby boom supplied a large number of young people who delayed putting down roots for an unusually long time. Changed attitudes are another reason: people are more cynical about government and politics and, it is hypothesized, less likely to vote. Another, more benign possibility: in a time of widespread prosperity and no general war, issues simply weren't so pressing for many people; so however much they grumbled to pollsters, they didn't bother to vote.

That may be changing. The 1982 elections saw a rising turnout, as compared with 1978--the first in 20 years. The baby boomers are aging, attitudes are a little more positive, and issues (the recession, for instance) may impinge more on people's lives. But keep in mind that the higher turnout doesn't necessarily mean more minority or Democratic voters. Blacks turned out in larger numbers in many states in 1981 and 1982. But in California higher turnout came mainly from opponents of a gun control ballot initiative; if it hadn't been for these new voters, Thomas Bradley would have become the nation's first black governor. Conservative activists now are urging their followers to register and vote. It's not clear that they have a motivating issue; but if they do, higher turnout may end up helping Reagan Republicans as much as liberal Democrats in 1984.

Low turnout has been called a danger to democracy. But it is more a symptom than a disease, and to the extent that it indicates that people don't feel much affected by government, it is not even that. Higher turnout may be evidence of health, but some of those who are calling for more turnout may not be pleased with the choices of those who vote for the first time in 1984.