Divide America into those who want to ease the plight of the poor and those who don't give a damn, and it's easy to choose sides. The harder choices involve not whether but how to help the poor.

Liberals, including virtually the whole of the black civil rights leadership, favor the programs that are increasingly in disfavor among the conservatives now in the political saddle: welfare, housing assistance, food stamps, school lunch programs, public-sector job creation and other direct federal help for poor people.

Conservatives, when they express concern at all, tend to emphasize not direct help but generalized opportunity. Improve the economy by "freeing" American enterprise, they say, and the result will be business expansion and its natural concommitant, morejobs for everybody.

Advocates of the poor point out, accurately, what Jesse Jackson said during his run for the presidency: that the "rising tide" of the general economy has failed to lift "the boats stuck at the bottom." Indeed, the economic status of the poorest 40 percent of Americans has declined during the period when the top 60 percent were doing well enough to make four more years of Reagan policies seem attractive.

But if the conservative approach to helping the poor hasn't worked, neither has the liberal approach. It's easy to forget, with all the anguish over Reagan's cuts of the social programs, that those programs were not effective in solving the problem of poverty.

It's easy to forget, for instance, a pre-Reagan National Urban League report ("Black Progress? Black Retrogression!") whose thrust was that blacks were no better off then than they had been 10 years earlier, or the drumbeat out of the civil rights hierarchy to the effect that black advancement was a "myth."

One of the problems has been the tendency to think of the black and the poor as a single entity, ignoring the fact that the economic, education and attitudinal differences between middle-class blacks and their low-income or jobless counterparts call for different approaches.

White America knows what the civil rights leadership refuses to acknowledge: that progress for middle-income blacks, while still woefully inadequate, is a fact, and that the influence of racism is fading to the point that that progress is likely to continue. But it is also true that ending racism does not result in significant change for what has come to be called the black underclass. The fact is that neither conservatives nor liberals, blacks nor whites, have come up with proposals to reduce the size of that underclass, or even to halt its growth.

It is clear enough that the "rising tide" has not helped. It is becoming clear that enacting the entire agenda of the black leadership won't help either. That agenda might, at considerable expense, make the underclass more comfortable in its poverty. But the poverty would remain.

The black leadership and other advocates of the poor must devise programs and approaches that address the unique problems of the long-term poor, whose poverty has cost them not just income but also ambition, education, discipline and hope. The possibilities are there, but they won't be found as long as we insist on seeing their plight primarily as the result of racism and hard-heartedness, and as long as we refuse to acknowledge that the problems of race and the problems of hard-core poverty are not the same.