In government, bicameralism (Latin bi, two + camera, chamber) is the practice of having two legislative or parliamentary chambers compromise bills. Bicameralism is an essential and defining feature of the classical notion of mixed government. Bicameral legislatures tend to require a concurrent majority to pass legislation.
[B]icameralism is common, in both parliamentary and presidential systems. Elected second chambers are relatively more common in presidential systems, in part due to United States influence, but the composition of second chambers varies widely, with indirectly elected, directly elected and unelected members often serving (in both presidential and parliamentary states) and with many chambers having a mixed membership between these groups. Second chamber powers also vary widely.
Far from being an anomaly, bicameralism is now the parliamentary system under which a broad majority of the world's populations live. It is also the system adopted by the world's wealthiest nations: of the fifteen countries with the highest gross domestic product, only two - the People's Republic of China and South Korea - have a monocameral Parliament.
House members long have railed against the Senate's use of filibusters and non-germane amendments. Many express frustration that House-passed measures may be inordinately stymied by the Senate's practice of extended debate or transformed substantively through non-germane floor amendments. A single Senator can block action on virtually any measure. By comparison, Senators are usually less vocal in their complaints about the House.
[I]f the two legislative bodies are controlled by opposite parties, most of the electoral incentives vanish and bicameralism could be worse than unicameralism for accountability purposes. The empirical analysis carried out on 35 democracies with different parliamentary structures largely support these predictions. In particular, we find that, while party polarization has an unambiguous negative effect on corruption, the relationship between bicameralism and corruption varies depending on whether the two chambers are divided or not. Only under unified party control is bicameralism associated with lower corruption, and this beneficial effect increases with the polarization of the electoral race.
We have found that governments that manage to command concurrent majorities last longer than governments with only minority support in the upper house, other things equal. We interpret this finding as supportive of the notion that policy-making success affects the longevity of governments in parliamentary systems, and we infer that politicians ought to pay attention to upper-house exigencies when constructing their governments in the first place.
Federal governments often have bicameral legislatures with strong federal representation in one of the chambers, as well as a written and entrenched constitution together with constitutional judicial review powers. A standard model is to give each federal unit (whether state, province, or Land) equal representation in one chamber, irrespective of population, and to require that chamber's assent for the adoption of new laws. This basic idea exists in Germany, South Africa, Australia, and similar or other variant systems exist in Austria, Brazil, Mexico, and many other states, as well as in the European Union.
In 1913, passage of the seventeenth amendment mandated that Senators would be elected by popular vote rather than chosen by the State legislatures. This action removed the most substantial constitutional difference between the Senate and the House and allowed the Senate to claim full legitimacy as a democratic institution.
Initially, using the British model, the legislature would be divided into two chambers. The idea was almost aristocratic in nature. The Senate would function as the Upper Chamber with longer terms and richer members, a small elite body that would review decisions and was deemed as more prudent and patient, with stricter qualifications. The house, as a concession to democracy, would be popularly elected based upon population counts and would be considered a Lower Chamber, made up of men with less money and prestige. The Senate was to be a "cooling saucer" according to George Washington, a place to insulate the nation from the whims of the common population in pushing their interests through the House of Representatives at the expense of the wealthy.
The history of bicameralism in England suggests that the institutional evolution was driven by societal forces rather than a theoretical understanding of political institutions. Nonetheless, in part because of the stability and power of the British state, its political institutions became a model of efficient and stable government.
Many argue that the increase in partisan polarization in the last several decades has exacerbated Congress's tendency toward gridlock (Nivola and Brady 2008). ... Yet most congressional leaders will tell you that, once a bill has passed both chambers, the prospects of inter-chamber agreement are considerably higher than a naive bicameralism theory would lead one to expect.