THE idea of a permanent underclass in American society -- of whatever color -- is simply not acceptable. Perhaps this issue surfaces forcefully now because of the first observance of Martin Luther King Day as a national holiday, providing a new annual checkpoint for measuring minority progress.
Also, this is the time of year when the national budget debate begins in earnest in Washington, and the case for domestic spending vs. military spending must be argued again.
And President Reagan is expected to announce a major, year-long review of the whole ``social safety net'' -- Aid to Families With Dependent Children, medicaid, food stamps, housing assistance, supplemental security income, and the Women, Infants, and Children (WIC) nutrition program -- in his State of the Union message.
It is to be hoped that such a review will be motivated by compassion and concern for the effectiveness of these programs as well as by cost-cutting.
Statistics continue to show that while the majority of blacks are advancing economically with mainstream America, many blacks are not. A tangle of problems no one fully understands has excluded them from full participation in society. This black underclass has been deprived not only of a fair slice of the pie but of the opportunity to help in the baking.
The recent Bill Moyers television special, ``The Vanishing Family -- Crisis in Black America,'' has drawn new attention to one particular facet of the problem: the breakdown of black family life. As noted black scholar and lawyer Eleanor Holmes Norton has remarked, ``Repair of the black family is central to any serious strategy to improve the black condition.''
The Moyers program provided disheartening glimpses of young men whose idea of fatherhood extends no further than the act of begetting, and of young women who grew up without fathers themselves and thus conclude, as one of them puts it, ``Male figures are not substantially important in the family.''
Unfortunately, one of the most basic roles of parenthood, providing for the family, has fallen to, or been usurped by, the welfare check, which has proved a more reliable source of income than many black men are able to establish.
The chicken-and-egg debate over the welfare system and its effects on the work ethic has run on long and loud over the years. One growing trend, which has reached more than 20 states so far, is ``workfare'' -- requiring recipients to work for the aid they receive.
The debate needs to be continued, with emphasis on modifying the system to encourage more active roles for fathers.
Social systems that attempt to deal with such issues evolve painfully slowly.
But as the Moyers program suggested, the solution will be a matter of private morals as well as public policy. Young men and women must be supported -- by families, friends, schools, and society as a whole -- in seeing themselves and their potential as too precious to squander in irresponsible sex or the hair-trigger violence that plagues poor communities.
The notion that millions of Americans can be trapped in permanent eddies of poverty while the rest of society surges ahead cannot be accepted.