What is the relationship between the executive and legislative branches in a presidential government?

Most legislatures around the world select members via public elections, in which citizens vote for either a candidate or a political party to represent them in the legislature. There are three main types of direct legislative election systems: proportional representation systems, plurality or “first past the post” systems, and mixed systems. Within each of these sets of electoral rules, there are many variations, but all the political systems within a given type share certain common characteristics.

Electoral systems in which the relative level of support for political parties in the population is reflected in the legislature are proportional representation systems. If 10 percent of the public supports a particular political party and shows up to vote for them, that party can expect to hold roughly 10 percent of the seats in the legislature. The principle behind this system is that all preferences should be reflected in government, not just those views that have majority support. There are many different variations of proportional representation, often based on the way in which votes are translated into seats in government. Most variations of proportional representation require multimember districts in order to have seats to divide among the winners. In the lower house of Brazil’s National Congress, the 26 federal states and the federal district are each allotted between 8 and 70 seats, based on population.37 The electoral result in each district determines the number of seats the party will receive in the legislature; this combines proportional representation by party, in which the amount of support a party has determines the amount of seats they receive, with proportional representation by population, in which more populous regions receive more representation than less populous regions. Additionally, most systems have a minimum threshold of votes needed to gain seats in the legislature, ranging from 3 to 5 percent of the electorate in most countries. So although proportional representation allows smaller parties to gain seats, minimum threshold requirements are thought to prevent small fringe political parties from gaining seats in the legislature.38

In plurality or first-past-the-post electoral systems, voters cast a vote directly for the candidate of their choice, and the candidate with the most votes wins the election, regardless of the percentage of the vote share they secure. Because there is a direct relationship between votes cast and election outcomes in these systems, they are generally considered more straightforward than proportional representation systems. However, in these systems, it is extremely difficult for small parties to gain political power. Additionally, legislators can take office in these systems even if the majority of their constituents voted for someone else. For example, in the 2020 United States Senate race in Minnesota, Democratic candidate Tina Smith won reelection with 48.74 percent of the vote. However, because Republican Jason Lewis got 43.5 percent, Kevin O’Connor of the Legal Marijuana Now Party got 5.91 percent, and Oliver Steinberg of the Grassroots Legalize Cannabis Party got 1.78 percent, a larger total percentage of voters selected someone other than Tina Smith, the winner of the race.39 While plurality voting is most commonly used in single-member districts, it can also be used in multimember districts. In those systems, voters are allowed to pick as many candidates as there are seats up for election, and the candidates with the most votes win. For example, in a race with three open seats, voters may pick three candidates, and the three candidates with the highest vote totals win the election.

Mixed systems combine aspects of proportional representation and plurality voting systems. While every mixed system is slightly different, the South Korean National Assembly, where 253 seats are elected by plurality voting in single-member districts and an additional 47 seats are elected at the national level using proportional representation, provides a clear example of how these systems can work. Often, mixed systems use proportional representation seats to help balance out distortions in representation that arise from plurality voting. For example, if a party gained 44 percent of the vote nationally, but due to results in individual districts it received more than 51 percent of the plurality voting seats, the proportional representation–based seats could be adjusted to compensate for the less representative plurality results.40

In all of these systems, the direct election of legislators creates a system in which legislators are beholden to the people who elected them. That responsibility may be to the people who voted in support of their political party or to the constituents of their geographic districts, but regardless of the voting system, legislators who ignore the will of the people do so at their peril. Some systems offer more protection for individual legislators, such as proportional representation systems in which party leaders select individuals to fill seats, but ultimately, a legislator or party that routinely fails to respond to constituents’ desires loses the support of the people. Remember parliamentarian and philosopher Edmund Burke from the earlier discussion of representation? He practiced his idea that the proper role for a legislator was to be a trustee for his constituents and was voted out of office because people felt he did not sufficiently represent them.

The type of electoral system has a significant effect on the number of competitive parties in the political system. That relationship can be summed up by Duverger’s law, which states that political systems with plurality voting and single-member districts will have two competitive political parties in each race.41 In these systems, many voters are less inclined to vote for candidates representing smaller parties, fearing that doing so would amount to “wasting” their vote given the slim chance those candidates have of winning.42 This phenomenon occurs at the district level; for example, in a race for the United States Senate seat representing Illinois, only two political parties will be competitive. Duverger’s law does not guarantee that there will only be two competitive parties in the legislature. In some settings, two dominant parties do emerge in the legislature, as is the case with the Democratic and Republican Parties in United States politics, but in other settings, there may be different competitive parties around the country. Following the 2019 elections for the Lok Sabha, the lower chamber of the Indian Parliament, 37 political parties won seats. Yet in individual states, the parties that were most competitive varied considerably. In Gujarat, a state on the western border with Pakistan, the two most competitive parties were the Bharatiya Janata Party and the Indian National Congress, which together received over 95 percent of votes in the state. In the state of Andhra Pradesh, the two most competitive parties were the Telugu Desam Party and the Yuvajana Sramika Rythu Congress Party, which accounted for approximately 90 percent of votes in that state.43 Additionally, Duverger’s law does not guarantee that the two competitive parties will stay the same over time, as parties can cycle in and out of power. In the United States, the current Democratic and Republican party system44 replaced the Democratic and Whig party system, which replaced the Democratic-Republican and Federalist party system.45

In some systems, members of the legislature are elected not by the people but by other elected officials. The United States Senate used to be structured this way; members of the state legislatures, who were directly elected by the public, had the power to vote for members of the Senate. Though this practice ended in the United States in the early 20th century, similar practices still exist around the world. In the National People’s Congress in China, members of the national legislature are elected by the provincial-level legislatures, who are elected by lower levels of assemblies. This means that a successful delegate in the National People’s Congress must rise through many rounds of voting at successively higher levels of government, though the first level they must pass through is the public.46 This electoral design likely means that members of the National People’s Congress are more closely aligned with other elected officials and the political party than they are with ordinary voters.

In some systems, the executive has the authority to appoint members to legislative chambers. In systems with either an absolute monarchy or another supreme leader, that leader is empowered to appoint members to the chamber without any public input. Depending on the exact relationship between the leader and the legislature, the appointed members may have the power to propose and pass legislation that originates in the chamber, or they may only be able to approve or reject legislation created by others. Additionally, some places have institutions that claim to be legislatures but lack any independent legislative authority. For example, in Bahrain’s National Assembly, the members of the lower chamber, the Majlis al-Nuwab or Council of Representatives, are elected by the people, while the Majlis al-Shura, also known as the Consultative Council, is made up of 40 seats directly appointed by the king.47 All legislation originates in the Council of Representatives, but in order to become law, it must also be approved by the Consultative Council. However, because of the king’s role in selecting and reappointing members, members of the Consultative Council may feel an obligation to support or oppose a piece of legislation based on the king’s preference, rather than their own. Brunei, on the other hand, only has one chamber, a legislative council whose members are appointed by the sultan. That council does not have any independent lawmaking authority, in part because the sultan, the crown prince, and the cabinet are also on the legislative council.48 Instead, the sultan creates all laws, and the function of the council is to be a venue for the sultan to discuss different policy ideas.

In other systems, legislators are appointed by a chief executive, such as a president or a prime minister, who is directly accountable to the people. In the Parliament of the Bahamas, the governor-general, in consultation with the prime minister and the leader of the opposition, appoints members to the 16-person Senate. The prime minister alone gets to select nine members, the leader of the opposition gets to select four members, and, after consulting with the leader of the opposition, the prime minister selects an additional three members.49 While the public does not directly select the members of the chamber, the leaders who appoint them routinely face public elections. Although public accountability is more distant, a change in the Bahamian public’s support for a political party would result in significant changes to the membership of the Senate, which may help make those senators more responsive to the public.

Executive appointments can also be used to fill a vacancy between elections. In the United States Senate, a state governor can appoint an individual to fill a vacant seat for the remainder of the term.50 The appointed senator then must go up for reelection, so although there may be some sense of obligation between the senator and the governor who appointed them, the upcoming election increases the likelihood that the appointee will be responsive to their constituents.