IT WAS NOT at all the easy victory that so many in Baltimore had been glibly forecasting, but challenger Kurt Schmoke did defeat incumbent Clarence H. (Du) Burns for the Democratic nomination to be mayor of the city. And because winning this round is almost everything -- Baltimore's Democratic registration is overwhelming -- Mr. Schmoke, who has been Baltimore's state's attorney, can look forward to a much softer ride in the general election and on to the start of a new political era in the city.

Above all, this election was a generational contest, with the young man of promise ousting the older dedicated transition leader who had inherited the top job and heavy primary support from Gov. William Donald Schaefer. Mr. Schmoke also stands to be Baltimore's first elected black mayor; the accent here is on elected, since -- thanks to the able if brief leadership of Mr. Burns -- the city already has adjusted with great ease to stewardship by blacks as well as whites. Mr. Burns, in fact, came extremely close to winning on Tuesday.

Racial lines were crossed in the other key primary vote too -- with the victory of former city council member Mary Pat Clarke, who is white, to be council chairman. She has been politically close to Mr. Schmoke, though her independence from conventional party organization politics has been a trademark.

How these two leaders will convert their individual styles, their criticisms of local government and their less-than-warm relations with Gov. Schaefer to the responsibilities they stand to take on is not at all clear. What does seem clear is that Baltimore has opted for a decidedly new partnership to direct things in the coming years.