The question presented to the Supreme Court:

Under the federal bribery statute, Hobbs Act, and honest-services fraud statute, 18 U.S.C. §§ 201, 1346, 1951, it is a felony to agree to take "official action" in exchange for money, campaign contributions, or any other thing of value. The question presented is whether "official action" is limited to exercising actual governmental power, threatening to exercise such power, or pressuring others to exercise such power, and whether the jury must be so instructed; or, if not so limited, whether the Hobbs Act and honest-services fraud statute are unconstitutional.

From the syllabus of the opinion (available here):

© The Government’s expansive interpretation of “official act”would raise significant constitutional concerns. Conscientious public officials arrange meetings for constituents, contact other officials on their behalf, and include them in events all the time. Representative government assumes that public officials will hear from their constituents and act appropriately on their concerns. The Government’s position could cast a pall of potential prosecution over these relationships. This concern is substantial, as recognized by White House counsel from every administration from that of President Reagan to President Obama, as well as two bipartisan groups of former state attorneys general. The Government’s interpretation also raises due process and federalism concerns. Pp. 22–24.

2. Given the Court’s interpretation of “official act,” the District Court’s jury instructions were erroneous, and the jury may have convicted Governor McDonnell for conduct that is not unlawful. Because the errors in the jury instructions are not harmless beyond a reasonable doubt, the Court vacates Governor McDonnell’s convictions. Pp. 24–28

Some background is here and here.