1.) US Constitution. Article 1 Section 4. The Times, Places and Manner of holding Elections for Senators and Representatives, shall be prescribed in each State by the Legislature
2.). PA legislature passes law allowing mail in voting. Law requires ballots to be received no later than 8:00 PM Election Day. And that NO ballot received after 8:00 shall be counted. The Act also states that all sections of act are nonseverable. And if any section of act is held invalid, then the remaining sections of act are void.
3.)PA Supreme Court rules that ballots received after 8:00 shall be counted. Their ruling invalidates the 8:00PM requirement which voids the entire law that allowed mail in voting.
YouTube here.
http://youtu.be/cPzUxp5er8Q