I disagree with moms who say this wasn't bullying. I'm a school counselor (previously elementary school and now Jr. High) and I always define bullying to my students as "anything someone does to intentionally hurt you". I don't care if it happens once or a thousand times. Bullying encompasses all the mean things people to do to others to bring them down and get some sort of 'boost' for themself (of self-esteem, attention, laughs, power, what have you).
Otherwise they think of bullying in the classic sense (a kid who beats you up for your lunch money day after day) when it is so much more complex then that. Kids need to understand how common bullying is, and be aware that they may even find themselves acting a bully sometimes. It doesn't have to be some big serious scary thing--- it is something that happens often, and can be corrected, worked on, dealt with.
IMO, that was a bullying incident. But whatever, it doesn't matter what we label it; it was rude, he hurt your daughters feelings, it should be addressed.
Start with the teacher. If not, call the counselor (if they have one?). I would go to the principal as a last resort, no need to go to the top of ladder right away, ya'know. If the kids are in the same class, let teacher take care of it. Teachers usually tell this stuff to their principal anyway, to keep them in the loop, but they like to be given the chance to handle it. Especially if mom is known around campus, word will probably get back to the principal in the casual staff banter that goes around.
I always think about if the roles were reversed. If my own kid ripped up someone's campaign sticker on the playground, I would hope an adult would correct the behavior and give me the chance to address it at home. I hate the thought that my own kid could be doing some mean stuff at school and I would never know.
Not trying to make a mountain out of a molehill here but as a counselor I am sensitive to bullying incidents, and I am also the student council advisor, I know how much guts it takes for kids to put themselves out there like that and run for office!
and PS: Personally, I've seen a lot of PTA alpha-moms over the years whose kids are not the best-behaved! Not enough to generalize... but enough to "make you go hmmmm" ;)
OH, and may I remind everyone these kids are in THIRD GRADE> he is just plain being mean. Not "exercising his free speech" or "just expressing his personal opinion that she wouldn't be a good leader". Sure he is entitled to his opinions but I think we all agree that we want our kids to be kind on the playground. My daughter may think little Johnnie is a big fat jerk but the last thing I want her to do is announce it to everyone or tell others that's what she thinks and they shouldn't be his friend or something. I think the old rule applies, IF YOU DON'T HAVE ANYTHING NICE TO SAY.... sure it is a "political election" but it is still elementary school folks.