The Republican National Committee agreed yesterday to obtain federal court clearance for any future "ballot security programs," which Democrats have charged the GOP has used to harass black voters in the past.

The out-of-court agreement requires the RNC to file plans for any ballot security program with the Democratic National Committee and a federal court and receive the explicit approval of a federal judge before proceeding.

The agreement, filed in Newark, N.J., is designed to settle a $10 million suit brought by the DNC last October over a Republican effort to purge voter rolls in Louisiana. It still must be approved by U.S. District Court Judge Dickinson R. Debevoise.

An internal GOP memo obtained by the Democrats during the discovery process said the program "could keep the black vote down considerably." The DNC charged that the program violated federal civil rights laws and a 1982 consent order signed by both parties.

Under the order, the RNC was to "refrain from undertaking any ballot security activities in polling places or election districts where the racial composition of such districts is a factor."

Jane Frank Harman, chairwoman of the DNC Lawyers Council, said the agreement "will effectively put an end" to GOP efforts "to target and disenfranchise minority voters with so-called ballot secruity programs."

"We're tremendously pleased with the agreement," RNC communications director Terry Wade said. He noted that the settlement did not include a finding that the RNC violated any law, nor did it call for payment of damages.

"Democrats tried to make a political issue out of our ballot security program," he said. "We believe our programs will be approved by the court and we can prevent telephone poles and dead people from voting."

In the GOP program, voters in districts and precincts in which 80 percent or more cast ballots for Walter F. Mondale in the 1984 election -- precincts that in many cases are heavily black or Hispanic -- were mailed letters marked "Do not forward, return to sender."

Letters returned to a Chicago company hired by the GOP, Ballot Integrity Group Inc., were turned over to election officials in an effort to have the names purged from the lists on grounds that the voters did not live at their listed addresses.

In addition, those names were given to the FBI and U.S. attorney's office. The names were also kept for possible use by Republican poll judges on election day.

The Louisana effort was designed to help former Republican House member W. Henson Moore in his unsuccessful 1986 Senate race against John B. Breaux (D-La.).

In a memo obtained in the case, Kris Wolfe, the RNC's political director in the Midwest, wrote:

"I know this race {in Louisiana} is really important to you. I would guess that this program will eliminate at least 60-80,000 folks from the rolls. . . . If it's a close race . . . which I'm assuming it is, this could keep the black vote down considerably."