Describing modern politics is like buying the right chew toy from  a herd of salescats. None of them can answer your questions and they’re all lying to you in ways that you may never pick up.

My guess is that the Browncoats belong to the political party where you watch (well-written and highly enjoyable ) schlock television instead of taking out the garbage for your mom, that vanguard of the Alliance.

I WOULD love to see something new set in that same world though… but there’s a real and huge risk of anything like that coming off as a pale shadow.

They are not Libertarians wanting the freedom to do business the way they see fit. The captain maybe, but the rest of them very much depend on the formal rules of the civilization they are a part of. Even the escaped convict/mutant, looking to gather evidence of their innocence, so they may stay within the system.

The Alliance are the Conservatives, wanting things to stay the same, to keep control, while the rebels want the chance to do things their own way…

In fact, I don’t think there’s really strong parralels that can’t be argued either way here, I think it’s mostly a Global Empire vs the disparate rebels, without any very strong links to modern political forces, or you’d have heard about it on Fox

If you think about it, the Browncoats are the conservatives, they desire small government and like things just the way they are, thank you very much.  They are more like Libertarians than Republicans, they want the freedom to do business the way they see fit, on their own accord.

Whereas the Alliance decided that they knew better, that they could MAKE people better. They wanted to unify everyone under one rule, one overreaching government where they felt they could achieve utopia. They’re the reformers, the ones who want to usher in sweeping change. 

If you want to know the man’s voice, listen to the director’s commentary on the last Firefly episode Objects in Space.