Amendment 15 1. The right of citizens of the United States to vote shall not be denied or abridged by the United States or by any State on account of race, color, or previous condition of servitude.
Amendment 19 The right of citizens of the United States to vote shall not be denied or abridged by the United States or by any State on account of sex.
Amendment 24 1. The right of citizens of the United States to vote in any primary or other election for President or Vice President, for electors for President or Vice President, or for Senator or Representative in Congress, shall not be denied or abridged by the United States or any State by reason of failure to pay any poll tax or other tax.
(For a history of why the 24th Amendment only applies to federal elections, see here).
Amendment 26 1. The right of citizens of the United States, who are eighteen years of age or older, to vote shall not be denied or abridged by the United States or by any State on account of age.
Notice how they all say, the right of citizens shall not be abridged or denied or something to that effect.... not that the PRIVILEGE as some have stated here.... or that aliens don't or can't have that right..... “Alien suffrage was quite common during the nineteenth century, coming to a peak in 1875 when twenty-two states and territories granted aliens the right to vote.”237 That ended in the 1920s, at which point all states required citizenship as a condition to voter eligibility.238 Today, every state prohibits noncitizens from voting in federal elections.239 Federal law, too, prohibits aliens from voting in federal elections.240
(federal law... not the constitution... just as a point) There are, however, jurisdictions that allow,241 or seek to allow,242 noncitizens to vote in local elections. And as resident aliens have a significant interest in the locales where they reside, and are subject to other political obligations like taxation, there have been particularly strong arguments in favor of extending suffrage to at least a set of them.243"
http://joshblackman.com/blog/2013/05/09/does-the-u-s-constitution-allow-non-c...