When viewed from an international perspective, three other features -- the extraordinary scope of its powers, its drastic misapportionment, and the exceptional weakness of its leadership structures -- make the U.S. Senate a true global outlier. Further, each of these features has a significant (and often negative) impact on American democracy, politics, and policymaking.
The Senate is an Exceptionally Powerful Upper House: The Senate shares full legislative, budgeting, and oversight authority with the House; it also has additional powers to confirm executive nominees and to ratify treaties. However, among legislatures in the world's established democracies, the norm is for upper houses to be decisively weaker than lower houses. Besides Italy, no other member of NATO, the European Union, or the G-8 has an upper house whose power matches that of its lower house.
Indeed, of the 23 countries that have been independent and continuously democratic since 1950, only three besides the U.S. have powerful upper houses. The remainder are either unicameral, and hence have no upper house at all, or apply a version of the so-called "one-and-a-half house" approach. Under this approach, weak upper houses play a role by reviewing legislation, voicing minority opinions, and suggesting amendments. But they rarely initiate major bills and, most importantly, they can be overridden by the lower house in cases of disagreement.
Such constitutional arrangements greatly streamline the legislative process and facilitate the creation of coherent public policy. In contrast, political systems with two equally powerful chambers, such as Italy and much of Latin America, are much more prone to ineffective governance of the kind we've been witnessing in Washington D.C.
The Senate is Extraordinarily Malapportioned: If the concept of "one-person, one-vote" is the modern gold standard for the allocation of political power, then the Senate is easily one of the world's least representative legislative houses. Wyoming's population of 576,000 is 66 times smaller than California's 37 million -- yet both have two US Senators. Likewise, North Dakotans have 38 times the per capita influence of Texans in the Senate, and Vermonters have 31 times the Senate clout of their neighbors in New York.
When translated into votes on the Senate floor, the nine most populous states represent just over 50 percent of the population but have a mere 18 Senators. The 26 smallest states have a majority of 52 Senators, but include only 18 percent of the national population.
The small-population states have repeatedly benefited from their outsized representation in the Senate by receiving disproportionate funding in such policy areas as food and nutrition, community development, environmental quality, disaster relief, and homeland security. Although some other democracies also have malapportioned upper houses, those upper houses tend to relatively weak and thus their policy impact is much less pronounced.
The Senate is Largely Leaderless: Although the Senate Majority Leader is often equated with the Speaker of the House, by comparison the power of the Senate's top figure is ambiguous and diffuse. Unlike the Speaker, the Senate Majority Leader has no Rules Committee and few other tools to determine the flow of legislation or to limit the amount of deliberation, debate, and delay on the floor. Senator Robert Dole once opined that he was not "the Majority Leader, but the Majority Pleader."
The major difference between the houses, of course, is that individual Senators can and do make creative use of that chamber's expansive rules of debate and amendment -- including, yes, the filibuster, which was only partly reformed by last week's actions by Senate Democrats.
Virtually nowhere else in the world can a single rank-and-file member of a legislature so easily bring the work of the entire legislature to such a halt. And as a consequence, few other legislative chambers have leaders who are so weak relative to the average member, and thus so unable to set coherent goals or to move the institution beyond impasses. Former Senate Majority Leader Trent Lott got it about right when he termed his autobiography Herding Cats.
So can any of this be meaningfully addressed? Reform of the Senate has been discussed for almost as long as the Senate has been in existence, and change does not come easily. However, last week's events show that incremental reforms are achievable. The year 2013 also marks the centennial of the 17th Amendment, which ushered in huge changes by mandating the direct election of Senators -- and also made it clear that sweeping reform of the Senate is indeed possible.
These debates are sure to continue, but in the meantime it's valuable for Americans to understand our unusual upper house as it really is, and not as we may assume it to be.