It wouldn't matter. Either one is fine.
I saw a huge lawn sign last week that said
JOHN and SARAH For America. I thought it was weird !
What next
Barack and Joe for America, They ought to stick with last names on signs !
It doesn't really make a difference, but I'd put 'vote.' A single person can't elect a candidate (unless he/shes the only one voting) but they can vote for somebody...