We in the US tend to assume that — however awful we might think our politicians are — our political system is excellent. The Constitution is held in high esteem across the political spectrum, and Democrats and Republicans alike pay lip service to the "genius" of the Founders. But our system, combining two powerful legislative bodies with a strong executive, is pretty rare internationally. Indeed, it appears to be a weaker model than most; the US is the just about the only country to sustain a presidential system for a long period without descending into dictatorship.
We can learn a lot from other countries' models, which are often more streamlined and democratically representative than our own. The best of the bunch, in my judgment: New Zealand.
The world's best electoral system
If you pay any attention at all to American politics, you know that Republicans have a healthy majority in the House of Representatives, with 246 seats (56.6 percent) to Democrats' 188 (43.2 percent; one seat is vacant). But their popular vote margin — 51 percent to 45.3 percent — was about half the size of their seat margin.
The differential was even more dramatic in 2012. House Republicans lost the popular vote, with 47.6 percent to Democrats' 48.8 percent, that year, even as they won a sizable majority of seats. That's not a particularly common occurrence, but it does happen from time to time; in 1996, Democrats also won the popular vote for the House while not gaining a majority or plurality of seats.
The standard explanation for why this kind of thing happens is that Democratic House districts tend to be more Democratic, on average, than Republican districts are Republican. That means that Democratic votes are "wasted" running up the margins in safe districts, whereas Republican votes are spread out enough to garner more seats-per-vote. Reasonable people can differ over the extent to which this pattern is explained by gerrymandering or the fact that Democrats tend to naturally cluster together geographically (I'd argue that a fair districting system would take the latter into account but that's another matter).
But the fact that it leads to obvious injustices is hard to deny. It's not fair to Democrats living in rural Texas, or Republicans living in Manhattan that they will almost certainly never be represented by someone with their political views. It's not fair to Democrats and Republicans living in their own parties' safe districts that their votes count for less than if they lived in swing districts. It's not fair to those in swing districts who lose narrowly; if, say, a Democrat wins a seat 51 percent to 49, that means roughly half the district isn't seeing their interests represented.
This is not an inevitable feature of the political system, and as Reihan Salam noted in Slate, most other countries have devised a solution: proportional representation. There are a bunch of different ways to do this. One is creating multi-member districts, and then having voters rank candidates through a process known as single transferable vote (STV); this is what Rob Richie and the team at FairVote, the main US lobbying group on this question, advocate. The simplest system would be pure party-list representation, as practiced in the Netherlands and Israel, in which there are no districts, voters choose parties rather than candidates, and parties get roughly the same percentage of seats as they did votes; a milder version, as used in Spain and Norway, does this at the district level.
Either of these would be huge improvements over the US status quo. But neither is ideal. Single transferable vote systems are party-agnostic and can't ensure that parties are represented in proportion to the votes they received as well as a party-list system can. But pure party-list systems can lead to a destabilizing proliferation of small parties which are able to extract promises from the bigger parties in exchange for joining their coalitions.
Party-list systems make it hard for a single party to get a majority, which means that if, say, a party has 45 seats out of 100, it still needs to win over a party with 6 seats to govern. The 6 seat party then has significant power to demand stuff, out of proportion to its actual level of support. So ironically, this form of proportional representation can have patently undemocratic consequences. Stuff like this has happened frequently in Israel, with fairly deleterious results.
The best proportional representation (PR) system, then, is a twist on party-list voting known as mixed-member PR, or MMP for short. MMP has voters select both a candidate in their local district and a party they'd like to win a majority. Everyone who wins a district gets a seat, and then additional seats are given out to ensure that parties are represented in proportion to their share of the party vote. This has a number of advantages. Unlike party list representation, people still have representatives with at least some ties to their area, for whatever that's worth.
But more importantly, it means parties have to be organized enough to compete in a decent number of districts in order to have a shot. That discourages the kind of excessive party formation that happens under pure party-list representation, while still ensuring that smaller parties get some say.
Germany and New Zealand both use MMP, and the result in each case is a slightly altered version of a two-party system. It's rare for the major parties in either country to get an outright majority (though it appears the National Party might in New Zealand), but typically they have enough ideological allies in smaller parties to form a government nonetheless. Germany also has a tradition of grand coalitions between its two main parties, but New Zealand shows the system can work even when there isn't that kind of bipartisan collaboration (as, let's be honest, there wouldn't be in a hypothetical United States with MMP). Neither country has faced problems with government formation of the kind nations using purer party list systems often do. In 2011, New Zealand held a nonbinding referendum on its voting system, and voters opted to stay with MMP by a wide margin.
It's worth emphasizing how rare MMP is: only four countries (Germany, New Zealand, Lesotho, and Romania) use it. And none of the other three can claim New Zealand's other big advantage…
The worst thing about the United States Senate — besides its history as a bulwark for slavery and white supremacy, its flagrant violation of the principle of "one person, one vote," and its general contempt for even the most basic norms of fairness and equal representation — is that it's totally useless. All upper houses are. Lower houses of parliament are completely capable of drafting and passing laws on their own. See: New Zealand.
New Zealand isn't alone in having a unicameral parliament. Sweden, Norway, Finland, Portugal, Denmark, Israel, Iceland, and Taiwan do as well, to name a few. But it stands out for being unicameral while still modeled after the British system. Britain's House of Lords has gradually seen its power wane over the centuries, while Australia opted to foolishly give its upper house a patina of democratic legitimacy, and thus a greater claim to power, by making it directly elected. Canada has contented itself with a Senate that's more or less always been useless. But New Zealand decided to get it over with and cut the damn thing out altogether.
This may seem like a small thing, and it certainly is compared to truly impotent bodies like the House of Lords. But even weak upper houses can typically delay legislation if they want to, and force changes on occasion. Germany's Bundesrat, for example, has an absolute veto over constitutional changes; in other cases, if the Bundesrat rejects a bill passed by the Bundestag (the lower house) with a two-thirds majority, the Bundestag has to muster a two-thirds majority itself to overrule the veto. That puts New Zealand over the top; not only does it, like Germany, have mixed member proportional representation, but unlike Germany it doesn't have a meddlesome upper house. The sole legitimate democratic institution is the one elected to proportionately represent the population.
This is a relatively minor point in the scheme of things, but it's worth briefly extolling the virtues of constitutional monarchy. Generally speaking, in a parliamentary system, you need a head of state who is not the prime minister to serve as a disinterested arbiter when there are disputes about how to form a government — say, if the largest party should be allowed to form a minority government or if smaller parties should be allowed to form a coalition, to name a recent example from Canada. That head of state is usually a figurehead president elected by the parliament (Germany, Italy) or the people (Ireland, Finland), or a monarch. And monarchs are better.
Monarchs are more effective than presidents precisely because they lack any semblance of legitimacy. It would be offensive for Queen Elizabeth or her representatives in Canada, New Zealand, etc. to meddle in domestic politics. Indeed, when the Governor-General of Australia did so in 1975 it set off a constitutional crisis that made it clear such behavior would not be tolerated. But figurehead presidents have some degree of democratic legitimacy, and are typically former politicians. That enables a greater rate of shenanigans — like when Italian president Giorgio Napolitano schemed, successfully, to remove Silvio Berlusconi as prime minister due at least in part to German chancellor Angela Merkel's entreaties to do so.
Napolitano is the rule, rather than the exception. Oxford political scientists Petra Schleiter and Edward Morgan-Jones have found that presidents, whether elected indirectly by parliament or directly by the people, are likelier to allow governments to change without new elections than monarchs are. In other words, they're likelier to change the government without any democratic input at all:
New Zealand would already top the list of best political systems even if it were a republic. But its constitutional monarchy only strengthens the case.