I'm not sure I understand what work "on principle" is doing in this sentence.
What's the difference between voting against anyone who acts against your interests "on principle", and voting against anyone who acts against your interests "out of self-interest"?
(I am not suggesting that you shouldn't vote self-interestedly; arguably democracy works best when everyone does.)
What's the difference between voting against anyone who acts against your interests "on principle", and voting against anyone who acts against your interests "out of self-interest"?
(I am not suggesting that you shouldn't vote self-interestedly; arguably democracy works best when everyone does.)