I somewhat disagree with the other commenters.
They won’t ask you directly what your political leanings are, but that doesn’t mean the adcoms are apolitical in the interview. For example, i know from personal experience that interviewers aren’t afraid to discus public health policy, and although I’d love to believe they assess you objectively, I find it hard to believe that they separate their personal political bias from the responses you give.
Just don’t say anything that is controversial either way if such questions arise... like don’t say “we should have universal healthcare” nor “Medicare and Medicaid are the worst! Lol. Overall, just avoid bringing up any topic or question that could lead you to having to discuss a controversy of policy.
Try to be as neutral as you possibly can be.