Lawrence Lessig has this essay in The Daily Beast, explaining why the Commission on Presidential Debates breaks federal campaign law when it holds general election presidential debates that are, in fact, only open to the Republican and Democratic nominees. Thanks to the Center for Competitive Politics for the link.
And of course Lessig was the first candidate the Democratic powers-that-be pushed out of the primary — in fact, they changed the rules to keep him out of the debates. See, for instance, here:
http://www.dailykos.com/story/2015/11/3/1443735/-DNC-rules-change-leaves-Lessig-out-of-2016-Democrat-debates-forced-to-leave-the-race
Or look it up and find your own preferred references.
What part of the DEAD USA Const gives ANY power to the gerrymander Congress to enact ANY thing regarding Prez debates — in the 50 sovereign States ???
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Abolish the super time bomb Electoral College — a late DARK AGE scheme from Hell — due to the conspiracy of the slave and small States at the top secret 1787 Federal Convention.