Cass Sunstein has posted this draft on SSRN. Here is the abstract:

With respect to the election of the U.S. President, the U.S. Constitution is vague and full of silences and gaps. When the vote is close, and when people disagree about who won, the Constitution does not sort out the respective roles of the states, the Electoral College, Congress, and the Vice President. The Electoral Count Act of 1887 is the closest thing to a roadmap for handling controversies after election day, and on many issues, it offers helpful guidance. At the same time, it is not at all clear that it is constitutional, or that it is binding, and in the face of a claim of serious mistakes and fraud, it contains silence and ambiguity. Taken together, the Constitution and the Electoral Count Act answer numerous questions, but they also leave important ones unanswered, including the role of the House and Senate amidst allegations of fraud and the proper role of the Vice President. This brief primer identifies the main answers and the principal open questions.