A more rational explanation could be: this vote will significantly and directly impact your local elections (school board president, Sheriff, alderman, whatever

A more rational explanation could be: this vote will significantly and directly impact your local elections (school board president, Sheriff, alderman, whatever) which does actually impact you whether you believe it or not. When you go to the polls, then just happen to vote for national candidate or your state candidates because they're there. If that fails, I always fall back to: it is your duty as a citizen to make your voice heard, and if you don't vote you are abdicating your right to complain later or engage in any sort of civic discussion.