Q101. “Exactly where in the Constitution does it say that the President and Vice President cannot be from the same state? In the 12th amendment the wording leads me to think that the electors and the candidates cannot be from the same state.”
A. The Constitution doesn’t say that they cannot be from the same state. However, the 12th Amendment does say that electors may not vote for a President from their state and a Vice President also from their state. This issue came up in the 2000 presidential campaign when Texas Governor George W. Bush chose fellow Texas resident Richard Cheney to be his running mate. Cheney, who had served in Congress as a Representative from Wyoming, quickly changed his legal residence back to Wyoming to avoid the possible conflict for electors from Texas. Court challenges to Cheney’s change of residency were denied.
It is unlikely that two people from the same state would ever be nominated by a major political party. It is constitutionally possible however. If it ever came to pass, the party that won the ticket’s state would likely suggest to the electors that their votes for the President go to the presidential nominee and that the votes for the Vice President be given in honor of a party official. Electors in all other states, as mentioned above, would be free to vote for both of the party’s nominees.
http://www.usconstitution.net/constfaq_a6.html
Thank you very much!