Twenty-second Amendment to the United States Constitution
Some argue that the 22nd Amendment and 12th Amendment bar any two-term president from later serving as vice president as well as from succeeding to the presidency from any point in the presidential line of succession. Others contend that the original intent of the 12th Amendment concerns qualification for "service" (age, residence, and citizenship), while the 22nd Amendment, concerns qualifications for "election", and thus (strictly applying the text) a former two-term president is still eligible to "serve" as vice president (neither amendment restricts the number of times an individual can be elected to the vice presidency), and then succeed to the presidency to serve out the balance of the term (though prohibited from running for election to an additional term).
United States nationality law
Adult citizens of the United States who are residents of one of the 50 states or the District of Columbia (Washington, D.C.) have the right to participate in the political system of the United States, as well as their state and local governments, (with most states having restrictions on voting by persons convicted of felonies, and a federal constitutional prohibition on naturalized persons running for President and Vice President of the United States), to be represented and protected abroad by the United States (through U.S. embassies and consulates), and to live in the United States and certain territories without any immigration requirements.
Felons can vote in over 40 states, and in at least 2 while incarcerated. Felons can also serve jury duty if approved.