I think you can have more impact with a law degree. Until/unless the revolution succeeds, many ordinary people's battles will be fought in the legal system. You can do a lot of good for people with the training a law degree gives you, whether that is in labour law, as a public defender, or anything else.

I hear what you're saying though about law school being hard and very expensive - ultimately that's a decision you'll have to make for yourself. I'm lucky enough to live somewhere with interest free student loans so I can't really speak to that side of things.