[rktman]

So, who decides which “competing slate” is the valid one? Would SCOTUS weigh in then? Trouble in River City.

[frogjerk]

Would SCOTUS weigh in then?

Nope - they have no standing.

[Bigtigermike]

Pending lawsuits and other legal procedures there is no President elect Biden until these are resolved. If not then it could be resolved by the New Congress on Jan 6 or if not that then it might still be settle by state electors by noon Jan 20

[eyeamok]

The President of the Senate Opens and Counts the Votes, Pence can choose which ones to Open and which ones to Count.

[Bubba Ho-Tep]

So, who decides which “competing slate” is the valid one?

The way the process works is that the governor creates Certificates of Ascertainment, and those accompany the electoral votes to the National Archives. Without those certificates, the votes are invalid. The National Archives then sends the votes to Congress to be counted.