Here is a way that we might be able to make Citizrns United irrelevant. Under the authority to regulate interstate commerce require that all corporations be chartered by the Federal Government within one year. Have that void any and all state chartered corporations. Specifically limit the rights of Federally chartered corporations to exclude personhood (and any other rights that an extremist court might be inclined to give to them beyond what is stated in the legislation creating them). This can be done without amending the Constitution and would be much faster than amending the Constitution.