The Electoral College is a body of electors established by the United States Constitution, which forms every four years for the sole purpose of electing the president and vice president of the United States. The Electoral College consists of 538 electors, and an absolute majority of at least 270 electoral votes is required to win election. According to Article II, Section 1, Clause 2 of the Constitution, each state legislature determines the manner by which its state's electors are chosen. Each state's number of electors is equal to the combined total of the state's membership in the Senate and House of Representatives; currently there are 100 senators and 435 representatives. Additionally, the Twenty-third Amendment, ratified in 1961, provides that the District of Columbia (D.C.) is entitled to the number of electors it would have if it were the least populated state (presently 3). U.S. territories are not entitled to any electors as they are not states. Following the national presidential election, which takes place the Tuesday after the first Monday of November, each state counts its popular votes according to that state's laws to designate presidential electors. Nearly all states allot all their electoral votes to the winning candidate in that state, no matter how close the candidate's win, but two states rely on a variation of "proportional representation". Electors are typically required to pledge to vote for the winning candidate, but there is an ongoing legal dispute about whether electors are required to vote as they pledged. State electors meet in their respective state capitals the first Monday after the second Wednesday of December to cast their votes. The results are counted by Congress, where they are tabulated nationally in the first week of January before a joint meeting of the Senate and House of Representatives, presided over by the vice president, acting as president of the Senate. If a majority of votes are not cast for a candidate, the House turns itself into a presidential election session, where one vote is assigned to each of the fifty states, excluding the District of Columbia. The elected president and vice president are inaugurated on January 20. While the electoral vote has generally given the same result as the popular vote, this has not been the case in several elections, most recently in the 2016 election. The Electoral College system is a matter of ongoing debate. Supporters of the Electoral College argue that it is fundamental to American federalism, that it requires candidates to appeal to voters outside large cities, increases the political influence of small states, preserves the two-party system, and makes the electoral outcome appear more legitimate than that of a nationwide popular vote. Opponents of the Electoral College argue that it can result in different candidates winning the popular and electoral vote (which occurred in two of the five presidential elections from 2000 to 2016); that it causes candidates to focus their campaigning disproportionately in a few "swing states"; and that its allocation of Electoral College votes gives citizens in less populated states (e.g., Wyoming) as much as four times the voting power as those in more populous states (e.g., California).