> SCOTUS should have differentiated between different categories of corporation (using existing tax code distinctions), and prevented (at least) regular for-profit corporations (of any tax status) from political spending.

It's not obvious how that would have made any difference when a for-profit corporation could just give the money it wants to spend to an aligned non-profit to spend it in the same way. Unless you mean to prevent them from donating money to the non-profit, but then where is a non-profit supposed to derive funding? "All political speech can be funded only by government grants" has a pretty clear conflict of interest, and you would then somehow have to deal with for-profit entities that inherently engage in political speech like newspapers and cable news networks. Why should Comcast/MSNBC or Fox be able to dedicate unlimited airtime to political advocacy but not Intel or Ford?