Politics will necessarily have to be a part of it - even if you could bring fusion power to market in the next decade. Politics responds to the shape of the solution landscape, so I see working on technologies (and "social technologies") as one way to influence it, with possibly better ROI than just voting for people who promise to "fix things".

(Also, voting is really a low-hanging fruit, so the best response here would probably be "why not both?".)

My worries about engaging directly in politics - becoming a politician - is that I see it as a very inefficient process, in which you'll have to give away most of your morality (and possibly interest in the original problem) before you get in a position to effect big changes.