Every citizen of the United States who is at least eighteen years of age, who meets registration residency requirements which may be prescribed by law, and who is qualified to vote under this article, may vote in any state or local election. A voter shall have been, immediately preceding the election, a thirty day resident of the election district in which he seeks to vote, except that for purposes of voting for President and Vice President of the United States other residency requirements may be prescribed by law. Additional voting qualifications may be prescribed by law for bond issue elections of political subdivisions. [Amended 1966, 1970 & 1972]