Senator Bernie Sanders has proposed a constitutional amendment that would overturn the Supreme Court's decision in a case called Citizens United vs. FEC.

The Saving American Democracy Amendment states that: 
Corporations are not persons with constitutional rights equal to real people. 
Corporations are subject to regulation by the people. 
Corporations may not make campaign contributions. 
Congress and states have the power to regulate campaign finances. 
http://sanders.senate.gov/imo/media/doc/Saving-American-Democracy.pdf

A corporation does not have First Amendment rights to spend as much money as it wants, without disclosure, on a political campaign. Corporations should not be able to go into their treasuries and spend millions and millions of dollars on a campaign in order to buy elections. But when the Supreme Court rules that corporations are "people" with the same Constitutional rights as citizens, our democracy is in grave danger.