In Baltimore two weeks ago, Mayor Schaefer won renomination in the Democratic primary. In that heavily Democratic city, and against a little- known Republican, he is expected to win reelection easily. In Philadelphia last May, former city managing director W. Wilson Goode won the Democratic primary for mayor. He is the current favorite to win the November general election. So Baltimore, a majority of whose citizens are black, seems about to reelect a white mayor, while Philadelphia, a majority of whose citizens are white, seems likely to elect a black mayor.

These prospective results undercut the widespread assumption that, in municipal elections, voters will invariably support candidates of their own race. There is to be sure an old American tradition of favoring candidates of one's own ethnic or racial background. In New England, for generations Irish voters tended to support Irish candidates and Yankees to support Yankees. As immigration continued and populations grew more diverse, and as blacks from the American South and Hispanics from Latin America joined immigrants from all parts of Europe in the nation's great cities, ethnic politics grew even more complicated. This kind of politics has been ridiculed in some quarters. But often as not it has been the result of a rational calculus: of voters deciding which candidates would best serve the interests of their group.

The Democratic primary voters of Baltimore who chose Mr. Schaefer and the Democratic primary voters of Philadelphia who chose Mr. Goode seem to have made such calculations. The candidates they have chosen have strong credentials and records of fairness to citizens of all backgrounds. In some elections in these cities, as elsewhere, you will find almost all black voters lined up on one side and almost all white voters on the other. But in these elections, as in many contests across the country, you will not. The final results from Baltimore and Philadelphia are not yet in. But the voters in these cities have been more particular and--in its best sense--discriminating than some were inclined to give them credit for.