GERRYMANDERING is bad; 'Jessemandering' is good. Confusing?Gerrymandering - named for a 19th-century Massachusetts governor, Elbridge Gerry - is the practice of drawing legislative district lines in meandering ways so as to maximize one party's vote-getting power and to disadvantage the political opponents. It's frowned on, and is sometimes illegal. Jessemandering - coined herewith, with a nod to America's best-known black politician, Jesse Jackson - is the practice of drawing legislative district lines in meandering ways so as to maximize the voting power of mi norities. It's now mandated by the federal Voting Rights Act. Gerrymandering has gone on every 10 years, as state legislatures redraw district lines after each census. The party in control - while needing to make congressional and state legislative districts equivalent in population to meet the one-man, one-vote standard - tries to configure districts with its candidates in mind, e.g., by placing a Democratic majority in as many districts as possible. This year is no exception. Except that this year, redistricting is further complicated by federal requirements that district lines also enhance the power of black, Hispanic, Asian, and other minority voting blocs to elect representatives from their own ranks. Thus, wherever feasible, minorities must be grouped into districts in such a way as to virtually guarantee the election of minority candidates. Jessemandering - race-conscious political districting - is an uncomfortable compromise in a society that aspires to be color-blind. Its presumption that Americans are best represented by people of their own race seems to disavow the melting-pot dream. In today's America, though, the presumption is probably true. And race-conscious redistricting is in part a necessary remedy to decades during which - principally in the South but also in some Northern cities - black voting power was purposefully diluted to prevent the election of black candidates. The US Justice Department will review more than 1,000 redistricting plans this year. The department's civil rights division showed its teeth this month, when it vetoed parts of redistricting plans filed by Mississippi, Louisiana, and New York City. A side effect of race-conscious redistricting is that it can cost incumbents their secure seats. This is particularly nettlesome for the Democrats, who have more incumbents in both Congress and the state legislatures than the Republicans do. Across the country, Democratic lawmakers are in a quandary as they try to satisfy the Voting Rights Act without forcing party compatriots out of office. And talk about strange bedfellows: The Republican Party is actively cooperating with civil rights groups to force the drawing of Jessemandered districts, especially in urban areas - districts that will almost certainly vote Democratic. The GOP's probable motive is to improve the party's electoral chances in new, heavily white suburban districts.