Under the terms of the United States Constitution, someone who wants to become the president of America must be a natural born United States citizen who is at least 35 years old and who has lived as a resident of the US for 14 years. These are the only legal requirements for the position, but many people have many expectations of presidential candidates which could be considered informal requirements. Additionally, anyone wanting to run for president must have access to very large sums of money, as a campaign costs a great deal of money.
The terms of citizenship for presidential candidates are interpreted very strictly. Any person wishing to run must be a natural born citizen, meaning that immigrants are not eligible to run, no matter how long they have lived in the US. If a child of American citizens is born abroad, he or she is technically considered a natural born citizen, and can therefore run for president. The requirement for being a permanent resident in the US for at least 14 years is meant to ensure that anyone running is aware of general issues which impact the American people.
There are a few exceptions built into the Constitutional requirements for those wishing to run for president. For instance, nobody who has already been president for two terms can run again. Additionally, no one who has served more than two years in a presidential capacity even though he or she wasn't elected — for example, if the vice president becomes the president after an assassination — he or she can only be re-elected once. The Senate can also ban people who have been impeached from the presidency from running again.
Most Americans want their presidential candidates to be of good character. While a felon could technically run for president, his or her campaign would be unlikely to succeed. The morals and ethics of candidates are often carefully scrutinized, especially by their opponents, so those who wish to run for president try to keep their personal lives clean.
Many American presidents have been publicly religious, and almost all have had families as well. Although these two traits are by no means required to run for President, they are often expected. Experience is also an important aspect of a campaign. Most citizens prefer to vote for people who have served in public office before, since it implies that they are experienced in dealing with similar positions. Military experience is also expected of many candidates, especially those who are old enough to have served in a major war.
Another important aspect of running for president is public speaking and charisma. Presidents undergo a long, grueling campaign trail; criss-crossing the country in an effort to garner votes. While doing this, they must be able to speak persuasively and clearly about major issues even when they're tired. Charisma makes a presidential candidate more accessible to potential voters, which can strengthen a campaign greatly. One of the most well-known examples of this was the Kennedy campaign in 1960, when Kennedy appeared much more confident and charismatic in televised debates than his opponent, Richard Nixon.
Anyone wanting to run for president needs to be wealthy, or at least able to access a lot of funding during the campaign. Candidates generally spend hundreds of millions of US Dollars (USD) in the first few months of campaigning alone, and an entire campaign can cost between $700 million and $1 billion USD. Though much of this comes from fundraising, candidates still have to provide a substantial amount of money, especially at the beginning of a campaign.