I am a political scientist focused on parties, elections, and alternative voting rules. Much of my work concerns the pros, cons, and possibility of a multi-party system. I defended my dissertation in Georgetown University's Department of Government on May 15, 2017.
"Proportional Representation in American Cities"
Proportional representation (PR) lowers the bar for winning office. A party with ten percent of votes gets (roughly) ten percent of seats. What would it take to enact PR in the United States? Under what conditions might it be stable? We have 24 instructive examples in US history.
From 1915-48, powerless groups used ballot initiatives to enact PR in their cities: junior major parties, incumbent-party factions that could not win primaries, and, less often, third parties.
PR let those groups into government but did not end the need for legislative majorities. In many cities, the pro-reform groups made pre-election deals and sometimes formed electoral parties. When the largest of those groups began losing on policy, it decided to repeal PR.
We often hear PR would let people raise issues that existing parties ignore. Different sorts of policies would have different coaltions, and legislative majorities would differ across bills. This is possible but comes at a price. Big parties can move between coalitions with impunity, but when smaller parties do it, the big parties repeal PR.
Finally, I give the first quantitative history of PR in American cities using newspapers, archival material, and newly digitized data from five large cities. The largest part of these data comes from three most-different cities that tap the US experience with PR: Cincinnati (1929-57); New York City (1937-47); and Worcester, Mass. (1949-61). That portion of the data includes 5,127 roll-call votes, 126 unique legislators, 1,011 rounds of vote-counting under the single transferable vote, 1,001 candidates, and their party affiliations over 25 elections (20 of which had party-free ballots).