I had lunch with an American political philosopher the other day, who said that Saakashvili was right. Party list-based porportional representation, he said, is more prone to party-based corruption than systems of single-mandate/majoritarian parliamentarians, like the United States Congress. In both cases, businesses attempt to purchase political favors by sponsoring candidacies; but majoritarians are only beholden to their few sponsors, while party-listers are beholden to their party apparatus and thus corrupt on a national level. As a consequence of this difference, so I'm told, party discipline in the US is nothing compared to that of Europe, Israel, Georgia, and most of the world, which rely mostly on party lists to fill their parliaments.
A by-product of the majoritarian/party-list difference is that if a system has a mix of the two types of seats, the balance will usually shift over time in favor of more party list seats. After all, the parties have an incentive to unite on legislation to increase their power, while many majoritarians don't have a similarly strong reason to protect the status quo.
A mix of majoritarian and party-list seats means that voting schemes are more complicated in the rest of the world than they are in the US. The game theory implications of some of these voting and appointment schemes are Gordian and labyrinthine and esoteric and krazee. Here's a description of New Zealand's system, for example, from Philip Dorrell's amateur science site:
The MMP ("Mixed Member Proportional") electoral system gives each voter two votes – a party vote and an electorate vote. The party votes determine how many parliamentary seats from a total of 120 seats are allocated to each party. Every voter belongs to an electorate, and electorate votes are used to vote for a choice of electorate MP within each electorate.The system is so confusing that the government conducts regular polls to monitor whether or not voters understand the system by which they vote. But on the surface, the system seems fair, despite being confusing.
The 69 electorate MPs and the 120 party MPs are not separate sets of MPs. 120 is intended to be the total number of MPs, which means that the 69 electorate MPs must be a subset of the 120.
We can think of electorate MPs as replacing hypothetical list MPs. For example, if party X receives 25% of the vote, they will have 30 MPs in parliament. If there were no electorate MPs, then the first 30 members of party X's party list would become MPs. But if party X also has 25 successful electorate MPs, then those 25 electorate MPs replace 25 of the list candidates, leaving just the top 5 list candidates to receive seats.
But there's a problem: what happens if a greater number of electorate (at-large) candidates from a party win than are accounted for by the party list vote that the same party receives?
If the number of electoral seats won by a party is more than the number of seats allocated to that party according to their share of party vote, the excess of electoral seats is called overhang. The rule for dealing with overhang in New Zealand's MMP system is to increase the total number of seats by the size of the overhang, giving each party that has an overhang its correct number of electorate seats, while continuing to give other parties the same proportion of the original 120 seats as determined by party votes. [emphasis added]In other words, if party X split into two parties--Y and Z--where Y only runs majoritarians, and Z only runs party-list candidates, and if voters who formerly voted for X now voted a ticket of majoritarians from Y and the party list of Z, then party X could nearly double its representation!
I don't see why every country doesn't do the following: let at-large seats make up a majority of the seats (perhaps 2/3) in the House, and fill the remaining seats, according to porportion, by a vote on a separate place on the ballot. That way, if you're a Democrat who hates the local Democratic candidate, you can vote against him/her while still affecting the representation of Democrats in the House. And if you're a Green Party or Reform Party (Right-to-Life Party, for that matter) supporter, you can vote for the local Rep/Dem, and still vote in a national representative or two from your fringe party. Yes, it could elect another Hitler. But the third-directioners would be worth it.
Speaking of stupid electoral systems, it seems that bloc voting, used in Palestine, Spain and elsewhere, is a big part of the reason why Hamas won the recent parliamentary elections. Bloc voting basically means that each district elects some number of parliamentarians n, with each voter getting n votes and the top n vote-getters winning seats. This is a nominally porportional system--a popular candidate from a fringe party can get elected, etc.--but it actually strongly benefits the ruling party or coalition, who can run exactly n candidates and use their plurality to get all n elected. And if the ruling party is (like Fatah) disorganized and cannot keep its factions from running too many candidates, a more disciplined minority party (like Hamas) which runs n candidates (or even better, a few less than n) in each district can win sweeping victories without even having a plurality of support among voters!