(The influence of Polybius 2 Century "checks and balances of the Constitution of the Roman Republic reflects on the BC treatise.) British political philosopher John Locke was a big influence, and due process clause of the Constitution was part of Magna Carta (1,215) [10] is based on the customary law. Qualifications. President born in a United States citizen, could be at least 35 years old and at least 14 years must stay in the United States. Obsolete part, it says that instead of a natural-born citizen, at the time of adoption of the Constitution, a person can become a citizen. Adoption of the Constitution to citizens of the United States in time for qualifying reason for the block to expand, despite their place of birth, a founder of the United States before the birth of foreign sovereign loyalty As part was. Without this clause, no one will come into question since the founding of America to be president for thirty-five years. Succession. Section 1 states that the vice president succeeds the president is removed, the functions and powers of the office can not, dies or resigns while in office. Original text ("It will be") made it clear that school based on a play (the order will be carried out under the authority of the office) or (assuming permanent presidency itself). Designed, William Henry Harrison, John Tyler set the precedent that the succession after the death was permanent, since the practice was, when the president died in office. Today, the 25th Amendment provides that the Vice President in the case of death or disability.