SELDOM HAS so innocuous a statute as the draft registration law enacted as a response to the Soviet invasion of Afghanistan been so savaged by its detractors, looked askance at by the courts and neglected by those who are supposed to enforce it. Opponents of the law treated it as if it amounted to a revival of the draft, although all it requires is that young men register on their 18th birthday. Federal judges said prosecutions under it were unconstitutional infringements of free speech, although no one doubts that Congress has the right to pass conscription laws and no one should be able to exempt himself from prosecution under a criminal statute by criticizing it publicly. As for the government, it failed for several years to act vigorously to get young men to comply with the law and to prosecute those who, after ample warning, persisted in refusing to comply.

Now common sense seems to be prevailing. The Supreme Court this year upheld the constitutionality of prosecutions, and so there should be fewer delays and uncertainties. Now there is nothing to prevent convictions of the small number of defendants who are likely to persist in violating the law on grounds of conscience. At the same time, the severity of punishment should be tempered in sentencing. A federal judge in Los Angeles who had originally declared a prosecution unconstitutional now has sentenced a defendant to six months of "house arrest." This is one way to reconcile the need to enforce the law with the desirability of making the punishment fit the crime.

Common sense is prevailing as well on enforcement of the 1982 law barring men who have not registered from receiving money from federal college student aid programs. In the past the Department of Education required colleges to verify that male students had registered. This seemed a straightforward law -- why should violators of federal law be eligible for federal aid? -- but some colleges complained. The law was challenged in the courts and upheld by the Supreme Court last year. Even so, this year Education Secretary William Bennett is dropping the rule requiring colleges to verify registration, and is simply requiring male recipients of aid to sign a statement that they have registered.

Mr. Bennett observes that, according to spot checks, 98 percent of men are now complying with the registration law, and so he sees little need for verification by colleges. This seems a sensible bit of forbearance, cutting paper work and federal intrusion. The important point here, and with respect to prosecutions for failure to register, is that the law is being generally obeyed. The registration law can be criticized on policy grounds, and there may be a case for repeal. But it is about as minimal an interference with civil liberties as a society that wants to retain the option of conscription can impose.