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 presidential election
Like any other election in the United States, the eligibility of an individual for voting is set out in the Constitution and regulated at state level. The Constitution states that suffrage cannot be denied on grounds of race or color, sex or age for citizens eighteen years or older. Beyond these basic qualifications, it is the responsibility of state legislatures to regulate voter eligibility.