Zephyr Teachout, who teaches law at Fordham University, has identified anti-corruption as part of the US Constitution.     THE ANTI-CORRUPTION PRINCIPLE   She is expanding her arguments in a book to be published by the Harvard University Press.  An article by Lawrence Lessig traces Senator John McCain’s positions on this matter.  Definition of Corruption in the US

The Supreme Court case can be found on the SCOTUS blog.  http://www.scotusblog.com/case-files/cases/mccutcheon-v-federal-election-commission/