For more than 30 years, Cincinnati elected its city council using proportional representation, a system that let voters rank candidates in order of preference and enabled blacks to win several seats.

In 1957, a majority of Cincinnati voters decided to end the system, not because it wasn't working, but because it was working too well.

"It gave political minorities power," said Douglas J. Amy, a professor of political science at Mount Holyoke College in Massachusetts, "and there was a backlash."

That backlash extended to dozens of other U.S. cities that made use of similar voting systems, and now, Cambridge, Mass., is the only city that still elects its city council by letting voters rank their choices.

Under that system, a voter can assign a rank (1, 2, 3, 4) to each choice. If a candidate does not meet a certain threshold for first-choice votes, all of those votes transfer to voters' second choices.

The prevailing system throughout the United States now is "winner-take-all" voting, and blacks, who make up about 12 percent of the U.S. population, have trouble winning outside of a small number of single-member districts specifically drawn for them.

But proportional representation may be enjoying a resurgence in different forms across the country, said Amy, who has written extensively about the subject.

And at the Equity and Regionalism conference Friday in Oakland, elected officials and policy makers from around the Pittsburgh region will discuss ways of using proportional voting systems to give blacks and other minorities a better chance at winning political representation in any future merged city-county government.

"Pretty much every advanced western country except for France, Great Britain, Canada, and the U.S. has variations of proportional representation," Amy said. "It is by far the most popular system in the world."

Amy acknowledges that the ranking system may seem alien to U.S. voters, and he sees another approach known as "cumulative voting" as more likely to catch on.

Already in use in parts of Texas and Alabama, cumulative voting allows voters to cast as many votes as there are candidates. They can cast all their votes for one candidate or spread the votes around.

In a race with five candidates, for instance, black voters could pile all of their five votes on one black candidate. In 1988, voters in Chilton County, Ala., where blacks made up 10 percent of the population, used cumulative voting to elect the first black county commissioner in the county's history.

Cumulative voting may make sense in Allegheny County, because it is similar to the at-large system used to elect the Pittsburgh City Council up until the 1989 election.

Any changes, however, would be likely to require legislation in Harrisburg, according to Steve MacNett, general counsel for the Republican caucus in the state Senate.

"The concept would have to be tested against the home rule statutes and the election laws," he said.