You have probably noticed by now that a few of the issues above arise only when the Republicans keep the Senate. For example, if Democrats win the Senate and keep the House, the tie between the two Houses, discussed above, is unlikely to occur. In such a blue wave case, the question is: Can Mitch McConnell decide to count the slates before the new Democrat Senate is seated on January 3?
The simple answer is no: under current law, the votes must be counted on January 6. But some have argued that this law is unconstitutional because it infringes on the right of the current Congress to decide on procedural questions that are directly committed to it.
Even if Senator McConnell argues the ECA is unconstitutional, thereby invalidating its designation of January 6, he cannot unilaterally reset the date of the joint session. From the election of 1792 through the election of 1932, U.S. law set the date of the joint session as the second Wednesday in February; this was back when the President was inaugurated in March. But when the 20th amendment moved inauguration from March to January (to reduce the lame duck period), Congress updated the law with a new date for the vote count. U.S. law designated January 6 beginning with the election of 1936. It’s necessary for Congress to choose a date by law because the Constitution does not set a date, nor does it grant the President of the Senate the power to do so. Any joint session must be scheduled by law, including the cooperation of the House of Representatives.
McConnell would create a giant trap for himself if his caucus refused to participate in the January 6 counting session. Because any makeup session would require a new law, with the consent of the House, Nancy Pelosi could just refuse to reset the date. And if the joint session doesn’t meet before January 20 . . . well, Nancy Pelosi becomes Acting President. So it’s actually Nancy Pelosi, not Mitch McConnell, who may have the most to gain from arguing the ECA’s choice of January 6 is unconstitutional.
Furthermore, it’s unlikely that any joint session would count unless it meets the constitutional requirements of a quorum. The constitution mentions two different types of quorums: the first is a majority of members (of either house) to conduct business; the second is the quorum for the failsafe process to select the President and Vice President, should the electoral college count produce no winner. That second quorum requires a House quorum of at least one representative from two-thirds of the states, and the Senate quorum requires two-thirds of members present. As currently constituted, both the Democrats and the Republicans have enough members to block a joint session quorum under either standard. No joint session can meet with a quorum without bipartisan support.