This can be a serious offense ending in deportation. I found this on USCIS gov site: (D) 17/ UNLAWFUL VOTERS- (i) IN GENERAL- Any alien who has voted in violation of any Federal, State, or local constitutional provision, statute, ordinance, or regulation is inadmissible. (ii) EXCEPTION- In the case of an alien who voted in a Federal, State, or local election (including an initiative, recall, or referendum) in violation of a lawful restriction of voting to citizens, if each natural parent of the alien (or, in the case of an adopted alien, each adoptive parent of the alien) is or was a citizen (whether by birth or naturalization), the alien permanently resided in the United States prior to attaining the age of 16, and the alien reasonably believed at the time of such violatio n that he or she was a citizen, the alien shall not be considered to be inadmissible under any provision of this subsection based on such violation. This applies to voting before, on, or after the 30th of September 1996, so no one is clear on that one. If you are placed in removal proceedings, the good news is that there is a case, Woodby v INS, 385 US 276 (1966) that may require that you acted knowingly and willfully.
