Harvard students know the system well: every time they vote for their Undergraduate Council representative of their class marshal they are presented with a list or candidates and the option of voting for "as many or as few" candidates as they want.

It's called the Hare Proportional Representation System (PR) and Cambridge is the only municipality in the country that still uses it.

The system gives Cambridge politics its own distinct flavor: candidates run on slates, go city-wide and spend large amounts of time and energy identifying voters who would be willing to vote for them as their second or third choice candidate.

When Cambridge voters enter the polling booths tomorrow, they will rank their choices for City Council and the School Committee. Thus, voters write #1 beside the name of their first choice candidate, #2 beside the name of their second choice, and so on.

Counting the ballots according to the complex PR formulae will often take a week.

Candidates win their seats by accumulating enough votes to reach a quota determined by a complicated formula. Once candidates reach a quota, their surplus votes are redistributed to the other candidates on the ballot.

The least popular candidates in the early rounds are also dropped, and their votes are also redistributed.

So, how would a clever politician campaign to win under this system?

According to Professor of Government kenneth A. Shepsle, successful campaigns in a PR election "require an awful lot of organization and a lot of information."

"Usually when they are fairly organized, parties can instruct their voters how to [number their ballots]," Shepsle says. "What politicians do is work thorough established community organizations--families, religious, fraternal groups and encourage supporters in those organizations to coordinate their votes."

But because each individuals candidate cares most about getting him or herself elected, Shepsle says that such organizations aimed at coordinating votes are not associated with individual campaigns.

In addition to campaigning vigorously for first choice support, candidates muse seek voters who would list them as their second choice.

"Proportional Representation encourages people to campaign outside a support group and look for second and third place votes," says Shepsle. "[Candidates should] focus not only on one's own supporters but in building alliances; not steal [votes] but get second listings."

This year's council candidates seem to be running their campaigns in accordance with Shepsle's analysis.

Candidates agree that identifying and cultivating a core of supporters that will definitely give you their #1 votes is just as central t a PR campaign as it is to a plurality system.