CAMBRIDGE City elections are approaching--so just how low the turnout will be is a focus of speculation. Once the elections are over and the figures are in, political shamans will call on a wild variety of factors to explain the public's lack of interest. The limited significance of the races, the lack of substantial issues involved, the low "sex appeal" of the candidates, and, inevitably, the weather will all be blamed.

But too little attention will be paid to the significance of the fact that, across the country, a growing number of citizens are content to leave decisions about the running of the res publica to others. In the last congressional elections, only 38 percent of the eligible citizens went to the polls. This figure was the lowest in 45 years and in several states the turnout was the lowest since 1798. In effect, Americans are returning to the way of doing political business that was the norm before the civil rights movement.

ONCE again, it is all but impossible to argue that this democracy is run by the people who compose it. The University of Michigan's "American Voter" study, completed in 1960, showed that low income and fewer than eight years of schooling decrease the probability that a citizen will vote. A recent article in The New Republic by Robert Kuttner reported that 75 percent of upper middle class people vote while less than 40 percent of low income citizens do.

For years, the political system adopted literacy tests, polling taxes, and a registration system that effectively prevented the poor and the less educated from voting. Today, the outcome of our substantially different systems to regulate voting is pretty much the same.

And it is simply not true that the government either cannot or should not do more to encourage the reluctant to go to the polls. As it stands now, volunteers who organize registration drives in public streets a week before elections carry most of society's burden for tapping popular wisdom. Why not, as Kuttner suggests in his article, include automatic voter registration whenever a driver's license is issued? Or how about making welfare centers registration offices?

The nature of the objections to such suggestions is apparent. Nonetheless, these proposals have been adopted by only a few states.

In many European democracies, everybody is automatically registered upon turning 18. In Italy, where absentee ballots are not available, the government organizes special trains from the nations of Northern Europe so that immigrants can make trips--sometimes of thousands of miles--to vote in their home-towns. As a result, the democracies of Europe routinely see political turnouts of more than 80 percent.

Is all the trouble worth it? The answer depends on how much one values the system of government to which political leaders here pay so much lip service.

It is often argued that the indiference shown by voters here is an inevitable result of the democracy's aging. And it is true that Italy, Spain, Greece, Portugal are young democracies where citizens still remember what it means to conquer tyranny. Perhaps in such countries there is unjustified idealism about the power of the people. But is it really naive that Italian schools provide for courses on civic education and explicitly address the importance of political participation?

AMERICAN schools, in an addled misunderstanding of democratic respect for diversity of opinion, try hard to avoid such direct, coercive teaching--and democracy suffers. Schools where allegiance to the flag is taught have been the targeted with law suits.

At Harvard, the self-proclaimed bastion of freedom and intellectual cultivation, the percentage of undergraduates registered to vote in Cambridge is quite dismal. Although large numbers of students no doubt are registered in their home communities, the smallness of the percentage registered to vote here is surprising.

I compared the public lists of students registered to the student population in each River House. The percentages obtained ranged from a high 23 percent of Adams and Dunster to a low 17 percent of Winthrop, Leverett and Kirkland.

Further, during the last Congressional primaries, tantamount to election in Democratic Cambridge, only 31 percent of registered electors voted in the third precinct, which is made up almost entirely of Harvard students. This says a lot about the bond young Americans feel to their community.

The current situation is becoming increasingly oligarchic, with only a small minority of citizens interested in the running of the country. In this year of the 200th anniversary of the Constitution, and of Robert H. Bork--and consequently of constant talk of the rights of citizenship--sight should not be lost of the responsibilities.