A federal court order requiring a change in North Carolina's legislative districts has divided the U.S. Justice Department and state Republicans -- and forged an uncommon alliance between state Republicans and blacks -- in what is widely regarded as a test of Congress' 1982 amendments to the Voting Rights Act.

The Reagan administration challenged the lower court ruling and successfully urged the Supreme Court to accept the appeal. But state GOP leaders, citing "happy coincidence" between the interests of blacks and Republicans, see the redistricting plan bolstering the party's strength in the legislature and want to preserve it.

In January 1984, a panel of three federal judges declared that North Carolina's system of electing several legislators from a single district denied blacks full participation in certain instances. The panel said the plan therefore violated the 1965 voting rights law, which had been amended to permit judges to look at the "totality of circumstances" in deciding whether an election procedure results in discrimination.

In response, the General Assembly disassembled eight multimember districts and created 31 new districts with a single legislator elected from each. At the same time, state officials in the Democratic administration of Gov. James B. Hunt Jr. appealed the decision to the Supreme Court.

At the court's request, the Justice Department intervened last April. Its brief, submitted by Solicitor General Rex E. Lee, said the panel had incorrectly applied the voting rights law by giving blacks "guaranteed electoral success."

"Is a district court justified in insisting on 'safe' single-member seats even where black voters under a multimember plan have an equal opportunity to participate in the political process and to elect representatives of their choice?" the brief asked.

Between the state's appeal and the Justice Department's entry into the case, however, appointments by Hunt's successor, Gov. James G. Martin (R), gave the state Board of Elections a 3-to-2 Republican majority. The board decided early this month, 3 to 2, to withdraw from the Supreme Court appeal.

"The Martin administration has taken a fresh look at the thing," said Jim Trotter, the governor's legal counsel. Martin "feels that the multimember districts were discriminatory to blacks. He is also aware of the benefits to Republicans."

In 1982, Republicans held 24 seats in both houses of the legislature. In 1984, as President Reagan, Sen. Jesse Helms (R) and Martin swept the state, the GOP doubled its share, winning 38 seats in the 120-member House and 12 in the 50-member Senate. Fifteen of those seats were in new single-member districts.

The redistricting, which occurred mostly in major urban centers, resulted in creation not only of predominantly black districts but also of predominantly white suburban districts attractive to Republicans.

In 1984, 13 blacks were elected to the state House and three to the state Senate, an overall increase of three over 1982 and 12 over 1980.

The case originated with a suit on behalf of several black voters represented by the NAACP Legal Defense Fund Inc. Attorney General Lacy H. Thornburg, a Democrat, announced Wednesday that he would pursue the appeal, saying that he represented the other state officials who are also party to the suit.

Although all of North Carolina's black legislators are Democrats, leaders of that party have expressed concern about single-member districts, saying that blacks have succeeded in multimember districts and that isolating black voters would deprive liberal white Democrats of crucial black support.

The three-judge panel consisted of three North Carolina judges. Their decision, written by U.S. Circuit Court Judge J. Dickson Phillips, said, "The creation of each of the multimember districts challenged in this action results in the black registered voters of that district being submerged as a voting minority in the district and thereby having less opportunity than do other members of the electorate to participate in the political process and to elect representatives of their choice." results in the black registered voters of that district being submerged as a voting minority in the district and thereby having less opportunity than do other members of the electorate to participate in the political process and to elect representatives of their choice."