The clinton administration has commenced its yearly process of launching policy proposals destined, presumably, for a spot in the State of the Union Address - if not actual enactment. Among them is a plan to triple federal funding for after-school programs for children whose parents work. This issue has concerned Americans for decades. So-called latchkey children, returning to an empty home after school, sometimes get into trouble and often spend unproductive hours in front of the TV. But research on the subject is mixed. Alarms compete with assurances that, on average, these children do no worse than others in school. As with many issues involving children and learning, concerns vary with social context. Suburban kids return to presumably safe, though empty houses. Urban children may have more people around, but in more dangerous surroundings. For many youngsters, unsupervised time after school is one more factor working against individual progress. That factor is countered by a caring parent who helps organize afternoon hours, setting rules for safety and making clear what's expected. But for many children, and parents, after-school programs are the best option. Federal funds currently provide such programs for 380,000 children. The Clinton plan would allocate an extra $400 million, directed mostly to school districts that have gotten rid of "social promotion" - passing students to the next grade regardless of academic performance. That's logical, since social promotion has been most controversial in the same urban districts that have the greatest problems with unsupervised children after school. But will the extra funding make budgetary sense? Even relatively small amounts of new spending will run the gauntlet of offsetting trims and preserving the surplus for major priorities, like Social Security reform. At the least, Mr. Clinton has refocused attention on a perennial issue that all too easily slips from view.