Robert Natelson, a senior fellow at the Independent Libertarian Institute of Constitutional Law and a member of the scientific council of the Conservative Council of the U.S. Legislative Exchange, also argued that the power of a state legislature to appoint its constituents could not be absolute, otherwise states would be allowed to appoint their electors in a way that violated public trust (for example. B by auction, to sell their votes to the highest bidder). The date of approval by Congress is not set in the Constitution, so approval can be given either before or after the approval of a given pact by the states. Consent can be explicit, but can also be inferred from the circumstances. Congress may also impose conditions as part of its approval of a pact.  Congress must expressly approve any pact that would increase the political power of the states in a way that would interfere with the power of the federal government.  Another way to examine why states are ignored in presidential elections is to see which states vote consistently for either party. This table shows that 16 states voted Democratic and 22 Republican states in the five presidential elections from 2000 to 2016. Because of the win-take-all approach that states use to allocate their votes, these states and some others are almost sure to deliver all their votes to either candidate and are therefore ignored by the candidates. Only 9 of the 25 smallest states (with 7 votes or less) were eligible for general election campaigns. New Hampshire, Iowa and Nevada attracted attention because they were tightly separated battlefield states.