Six years after the late Harold Washington changed the course of Chicago politics, the movement that crowned him mayor has fractured, jeopardizing the brief era of black leadership he set up on City Hall's fifth floor.

The likely benefactor of the split is Richard M. Daley, the white, three-term Cook County prosecutor who unseated Mayor Eugene Sawyer in the Democratic primary. He heads into Tuesday's election with polls showing him a strong favorite to occupy the office his political boss-father held for 21 years.But if Daley does in fact defeat third-party candidate Tim Evans, the lone black in the race, and Republican Edward Vrdolyak, he will have to work fast to consolidate his power in the nation's third largest city. Another election will be held in 1991, when Washington's second term would have expired.

"One of the first things Washington faced - and handled well - was sending a message to the voters that didn't back him," said top Daley campaign aide David Axelrod.

"He told people in the predominantly white communities that his administration was going to be even-handed in distributing services, in appointments and all facets of government . . . then went out and did those things.

If Daley were to model himself on Washington, he would in a sense be continuing a tradition. Washington, the city's first black mayor, learned more than a few of his political tricks from the elder Daley.

"The old man liked to say `Good government is good politics and good politics is good government,' " recalled Eugene Kennedy, a Loyola University professor and author of "Himself," a biography of Richard J. Daley.

That translated into providing basic services, which Washington understood, Kennedy said.