SIGNS that black political leaders are securing their ties to the major-party mainstream - in 1984's case, the Democrats - are in their own best interest. Black American voters, of course, were not always so uniformly Democratic in their voting. For seven decades after Lincoln and the Emancipation Proclamation, blacks voted heavily Republican. Then in waves, notably in the 1930s with FDR's New Deal, then in the 1960s with the civil rights movement, blacks voters shifted to the Democrats overwhelmingly.
There is no law of political science that says they will always stay with the Democrats. In 1984 the Republicans have not prepared the way to reclaim black political allegiance. Blacks see Reagan economic policy as falling heavily on the more marginal work force they represent, and Reagan social policy as placing a higher priority on majority rights.
Nonetheless, blacks can stay home from the polls. And a Democratic defeat this November could make the Democratic Party appear not only lukewarm toward black needs, but impotent to deliver even if its heart is in the right place.
The Rev. Jesse Jackson knows this. His attempt to reach an early accord this week with Charles T. Manatt, chairman of the Democratic National Committee, reflects his grasp that black demands, if excessive, could create such bitterness that Jackson's candidacy would end up hurting both the black agenda and the Democratic Party. Manatt assured Jackson that in rules changes, allocation of delegates, and committee appointments for the party's July convention, the black candidate's interests would be considered.
Partly, the Jackson-Manatt accord reflects the progress of the presidential nomination campaign itself. Walter Mondale's 2-to-1 lead over Gary Hart looks more and more persistent. In the next three major contests, Maryland, Texas, and Ohio, Mondale appears to hold an advantage. Hart is still hitting Mondale and the party's establishment hard, attempting to revive his candidacy. But the process of coalescing within Democratic ranks for the convention is clearly under way.
There will be later estimations of the Jackson achievements. He has highlighted United States policies toward South Africa. He has taken a different tack on the Middle East. He has been outside his party's consensus on defense spending - Jackson wants to cut it by 20 percent - in favor of more social spending.
The Democrats could not win in November if they took Jackson's counsel in whole cloth. Neither could they win if Jackson took his followers off into a third party, wilderness journey. Nor would Jackson's gains for blacks via his candidacy be worth much without the Democratic Party as its vehicle.
If Hart loses decisively in Texas and Ohio, he will likely stay in the race to the California finale. But he too may soon join party leaders in the rituals of compromise and accommodation, following Jackson's example.
Eventually, the GOP may join again in a healthy competition for black votes. In the meantime, it is helpful for blacks to make mature political decisions and attempt to bring along a new generation of political leaders capable of dealing from strength with the major party establishments.