It's Amendment 20 Section 3:
If, at the time fixed for the beginning of the term of the President, the President elect shall have died, the Vice President elect shall become President. If a President shall not have been chosen before the time fixed for the beginning of his term, or if the President elect shall have failed to qualify, then the Vice President elect shall act as President until a President shall have qualified; and the Congress may by law provide for the case wherein neither a President elect nor a Vice President elect shall have qualified, declaring who shall then act as President, or the manner in which one who is to act shall be selected, and such person shall act accordingly until a President or Vice President shall have qualified.
An argument can be made about the nature of "failed to qualify." What if this failure to qualify isn't discovered until after the President's term begins? Is that President still unqualified via the 20th amendment?
If so, and if both Biden and Harris are found to not have qualified under the 20th amendment, Congress can then "declar[e] who shall then act as President." Furthermore, Congress can determine "the manner in which one who is to act shall be selected," perhaps meaning a special election, a vote in the House (either by delegation or member), or even reinstalling the prior President.
However, this would involve SCOTUS to interpret that "fail to qualify" is permanent, and doesn't expire at the oath of office even though the election was provably stolen by the new President who would otherwise have failed to qualify if the theft had been uncovered sooner.
-PJ
If enough states flip to give Trump the victory we are in uncharted territory.
It all depends on whether we are willing to fight or, like you, prefer to surrender.
9th bars denial of unenumerated rights if the denial is based on the enumeration of certain rights in the Constitution, - say the denial of a right to a fair election, anything less then a fair election erodes ones voting rights. THe USSC arguments ere all based on the soverignty of the state legislatures in presidential election.
10th gaurantees state sovereignty - maybe here is where the right to withdraw certification lies and demand some sort of redress. I wouldn't bet the mortgage on these approaches.