Ok, so my background is in history, not law, but here's a TLDR version of it. Since the Constitution vests the COUNTING of the electoral votes with the VP his is the sole decision of whether and what votes count. This came into play in the election of 1800 when Thomas Jefferson was the VP running for POTUS. When congress met to count the certified electoral votes Jefferson is opening up the envelopes and calling out the votes. He gets to the one from Georgia and it's shady as fuck and clearly unconstitutional. Problem is, those are the votes that Jefferson and AAron Burr need to win, and prevent a five way race in the House which they most likely would have lost. So anyway, without skipping a beat Jefferson announces the Ga electoral votes for himself and Burr and moves on to the next envelope.
From The Memoirs of Aaron Burr published in 1836...
"On the 11th of February the ballots were opened ... Mr. Jefferson was the presiding officer. On opening the package [of] endorsed Georgia votes, it was discovered to be totally irregular. The statement now about to be given is derived from an honourable gentleman, a member of Congress from the state of New York during the administration of Mr. Jefferson, and yet living in this state. He says that Mr. Wells (a teller on the part of the Senate) informed him that the envelope was blank; that the return of the votes was not authenticated by the signatures of the electors, or any of them, either on the outside or the inside of the envelope, or in any other manner; that it merely stated in the inside that the votes of Georgia were, for Thomas Jefferson four; and for Aaron Burr four; without the signature of any person whatsoever. Mr. Wells added, that he was very undecided as to the proper course to be pursued by the tellers. It was, however, suggested by one of them that the paper should be handed to the presiding officer, without any statement from the tellers except that the return was informal; that he consented to this arrangement under the firm conviction that Mr. Jefferson would announce the nature of the informality from the chair; but, to his utmost surprise, he (Mr. Jefferson) rapidly declared that the votes of Georgia were four for Thomas Jefferson and four for Aaron Burr, without noticing their informality, and in a hurried manner put them aside, and then broke the seals and handed to the tellers the package from the next state. Mr. Wells observed, that as soon as Mr. Jefferson looked at the paper purporting to contain a statement of the electoral vote of the state of Georgia, his countenance changed, but that the decision and promptitude with which he acted on that occasion convinced him of that which he (a federalist) and his party had always doubted, that is to say, Mr. Jefferson's decision of character, at least when his own interest was at hazard."
I can't speak for everyone, but the President of the Senate (Pence) can throw out votes from disputed states.
Ok, so my background is in history, not law, but here's a TLDR version of it. Since the Constitution vests the COUNTING of the electoral votes with the VP his is the sole decision of whether and what votes count. This came into play in the election of 1800 when Thomas Jefferson was the VP running for POTUS. When congress met to count the certified electoral votes Jefferson is opening up the envelopes and calling out the votes. He gets to the one from Georgia and it's shady as fuck and clearly unconstitutional. Problem is, those are the votes that Jefferson and AAron Burr need to win, and prevent a five way race in the House which they most likely would have lost. So anyway, without skipping a beat Jefferson announces the Ga electoral votes for himself and Burr and moves on to the next envelope.
Here's a 2004 article from The Atlantic about it... https://www.theatlantic.com/magazine/archive/2004/03/how-jefferson-counted-himself-in/302888/
From The Memoirs of Aaron Burr published in 1836...
"On the 11th of February the ballots were opened ... Mr. Jefferson was the presiding officer. On opening the package [of] endorsed Georgia votes, it was discovered to be totally irregular. The statement now about to be given is derived from an honourable gentleman, a member of Congress from the state of New York during the administration of Mr. Jefferson, and yet living in this state. He says that Mr. Wells (a teller on the part of the Senate) informed him that the envelope was blank; that the return of the votes was not authenticated by the signatures of the electors, or any of them, either on the outside or the inside of the envelope, or in any other manner; that it merely stated in the inside that the votes of Georgia were, for Thomas Jefferson four; and for Aaron Burr four; without the signature of any person whatsoever. Mr. Wells added, that he was very undecided as to the proper course to be pursued by the tellers. It was, however, suggested by one of them that the paper should be handed to the presiding officer, without any statement from the tellers except that the return was informal; that he consented to this arrangement under the firm conviction that Mr. Jefferson would announce the nature of the informality from the chair; but, to his utmost surprise, he (Mr. Jefferson) rapidly declared that the votes of Georgia were four for Thomas Jefferson and four for Aaron Burr, without noticing their informality, and in a hurried manner put them aside, and then broke the seals and handed to the tellers the package from the next state. Mr. Wells observed, that as soon as Mr. Jefferson looked at the paper purporting to contain a statement of the electoral vote of the state of Georgia, his countenance changed, but that the decision and promptitude with which he acted on that occasion convinced him of that which he (a federalist) and his party had always doubted, that is to say, Mr. Jefferson's decision of character, at least when his own interest was at hazard."