What incentive does a politician have to support nationalizing the power grid? It wont be a super splashy issue to tackle so it isnt worth doing it for the credit, and the different power companies of the world will just put their money into buying opposition to your effort anyways.

That's the problem with capitalism is that any single thing you would want to do that would impact some cocksuckers capital, and the threat alone makes it a necessity to pay to win in congress. Usually the only way stuff like this happens is because there is new capital entering the market that can afford to donate against the old capital to overtake them. Its just rich assholes all the way down.