The United States Congress is the legislative body of the United States of America, consisting of the House of Representatives and the Senate. Congress has a central role in the separation of powers and was established after the Great Compromise of 1787 between large and small states within the confederation, which by agreement established a bicameral system of legislative power. This system does not allow the adoption of radically different laws that would significantly change the political direction of the US. The reason for this is the domination of two political parties, the Republican and the Democratic, and the relatively complicated way of passing laws that are easier to defeat than to adopt in these two houses, thereby ensuring the status quo. Moreover, the electoral system ensures a high percentage of re-election of candidates for Congress, although citizens can vote for changes in the House of Representatives and the Senate every two years. The Congress has a wide range of powers, some of which derive from the Constitution, but also includes some that are not explicitly stated in the Constitution, but equally important.