Title: Politics of the United States
Content:  since the American Civil War, although other parties have existed. There are major differences between the political system of the United States and that of many other developed countries. These include the increased power of the upper house of the legislature, a wider scope of power held by the Supreme Court, the separation of powers between the legislature and the executive, and the dominance of only two main parties. The United States is one of the world's developed countries where third parties have minimal influence and almost no representation at the national and state level. The federal entity created by the U.S. Constitution is the dominant feature of the American governmental system, as citizens are also subject to a state government and various units of local government (such as counties, municipalities, and special districts).
Title: Comparison of U.S. state and territory governments
Content:  In the United States, the government of each of the 50 states is structured in accordance with its individual constitution. In turn, each state constitution must be grounded in republican principles. Article IV, Section 4, Clause 1 of the United States Constitution tasks the federal government with assuring that each state's government is so organized. All state governments are modeled after the federal government and consist of three branches (although the three-branch structure is not Constitutionally required): executive, legislative, and judicial. All state governments are also organized as presidential systems where the governor is both head of government and head 
Title: Parliamentary system
Content:  The United Kingdom's fused power system is often noted to be advantageous with regards to accountability. The centralised government allows for more transparency as to where decisions originate from, this directly contrasts with the United States' system with former Treasury Secretary C. Douglas Dillon saying "the president blames Congress, the Congress blames the president, and the public remains confused and disgusted with government in Washington". Furthermore, ministers of the U.K. cabinet are subject to weekly Question Periods in which their actions/policies are scrutinised; no such regular check on the government exists in the U.S. system.
Title: Federal government of the United States
Content:  The federal government of the United States (U.S. federal government or U.S. government) is the national government of the United States, a federal republic in North America, composed of 50 states, a federal district (District of Columbia, where the government is based), five major self-governing territories and several island possessions. The federal government is composed of three distinct branches: legislative, executive, and judicial, whose powers are vested by the U.S. Constitution in the Congress, the president and the federal courts, respectively. The powers and duties of these branches are further defined by acts of Congress, including the creation of executive departments and courts inferior to the Supreme Court.
Title: Public policy
Content:  Unlike the UK, the U.S. has a largely devolved government, with power at local, state and federal level. Due to these various levels of governance, it can often be difficult to coordinate passing bills and legislation, and there is often disagreement. Despite this, the system allows citizens to be relatively involved in inputting legislation. Furthermore, each level of government is set up in a similar way with similar rules, and all pump money into creating what is hoped to be effective legislation. Policy creation in America is often seen as unique to other countries.
Title: Presidential system
Content:  Subnational governments, usually states, may be structured as presidential systems. All of the state governments in the United States use the presidential system, even though this is not constitutionally required. On a local level, many cities use council-manager government, which is equivalent to a parliamentary system, although the post of a city manager is normally a non-political position. Some countries without a presidential system at the national level use a form of this system at a subnational or local level. One example is Japan, where the national government uses the parliamentary system, but the prefectural and municipal governments have governors and mayors elected independently from local assemblies and councils.
Title: Politics of the United States
Content:  The United States is a constitutional federal republic, in which the president (the head of state and head of government), Congress, and judiciary share powers reserved to the national government, and the federal government shares sovereignty with the state governments. The executive branch is headed by the president and is independent of the legislature. Legislative power is vested in the two chambers of Congress: the Senate and the House of Representatives. The judicial branch (or judiciary), composed of the Supreme Court and lower federal courts, exercises judicial power. The judiciary's function is to interpret the United States Constitution and federal laws and regulations. This includes resolving disputes between the executive and legislative branches. The federal government's layout is explained in the Constitution. Two political parties, the Democratic Party and the Republican Party, have dominated American 
Title: Divided government in the United States
Content:  In the United States, divided government describes a situation in which one party controls the executive branch while another party controls one or both houses of the legislative branch. Divided government is seen by different groups as a benefit or as an undesirable product of the model of governance used in the U.S. political system. Under said model, known as the separation of powers, the state is divided into different branches. Each branch has separate and independent powers and areas of responsibility so that the powers of one branch are not in conflict with the powers associated with the others. However, the degree to which the president of the United States has control of Congress often determines their political strength - such as the ability to pass sponsored legislation, ratify treaties, and have Cabinet members and judges approved. The model can be contrasted with the fusion of powers 
Title: Politics of the United States
Content:  The modern political party system in the United States is a two-party system dominated by the Democratic Party and the Republican Party. These two parties have won every United States presidential election since 1852 and have controlled the United States Congress since at least 1856. From time to time, several other third parties have achieved relatively minor representation at the national and state levels. Among the two major parties, the Democratic Party generally positions itself as center-left in American politics and supports an American liberalism platform, while the Republican Party generally positions itself as center-right and supports an American conservatism platform.
Title: List of countries by system of government
Content:  government is a "semi-presidential system combining party and government in actual operation". Under China's constitution, the Chinese President is a largely ceremonial office with limited power. However, since 1993, as a matter of convention, the presidency has been held simultaneously by the General Secretary of the Communist Party, the top leader in the one-party system who heads the Politburo Standing Committee. Certain states have been defined as having more than one system of government or a mixed system – for instance, Poland possesses a semi-presidential government where the President appoints the Prime Minister or can veto legislation passed by parliament, but its Constitution defines the country as a parliamentary republic and its ministry is subject to parliamentary confidence.

Question: under what political system does the united states government operate?
Answer: Presidential system.