Okay, strange English grammar, here we go. First, I'm going to establish that the direct object (noun) is "voice", based on your question. So I am assuming that the sentence is written as "...passionate political voice..." Based on those assumptions, this is my best explanation. Adjectives are a pain. We have cumulative and coordinate adjectives. Coordinate adjectives can be separated with a comma or the word and. Cumulative adjectives struggle to be rearranged and cannot be separated with a comma or the word and. Can you replace the comma with the word and? "He spoke in a passionate and political voice..." Can you reverse the order of the adjectives? "He spoke in a political passionate voice..." This sentence sounds really strange to a native speaker's ears. It is out of order and doesn't roll off the tongue. I would say no here. It isn't an easy concept to understand, but a few really good everyday samples to keep in mind when working with adjectives would be Christmas tree and fire truck. We say "green Christmas tree" or "first Christmas tree". We do not say "Christmas green tree" or "Christmas first tree". In similar situations, we would say "red fire truck" or "old fire truck" but not "fire red truck" or "fire old truck". I hope that helps clear things up a bit.

Sorry, here's the sentence: Mink used her passionate political voice to advocate equality for all citizen.

You need to give an example because I can't see what comma you are talking about. Passionate, political voice? passionate political voice? I understand the question just need to know what you see.