Article IV Section 1
Full Faith and Credit shall be given in each State to the public Acts, Records, and judicial Proceedings of every other State. And the Congress may by general Laws prescribe the Manner in which such Acts, Records and Proceedings shall be proved, and the Effect thereof.
Simply put, Congress must put rules in place to allow officials from one state to do the counting of votes in another state not their own.
Think of it as being like the final scene in the Kevin Costner movie The Untouchables when he swaps juries from another case.
We must make it so that there are no partisans in a state counting their own votes. Each state can have their own elections officials who count the votes in statewide races if they choose, but federal elections should be counted by officials from outside their own state, using the "full faith and credit" clause of the Constitution.
-PJ