Amendment 12 in the constitution states if the election can't be certified and Trump doesn't concede, all votes become void and the house decides.
At that point, each state is allowed one vote.
37 out of 50 states are republican.
Woah.
https://constitutioncenter.org/interactive-constitution/amendment/amendment-xii
As I understand it, by making the vote impossible to certify. Enough lawsuits and you can make the legislature not certify the results and thus choose not to send electors
(Not a lawyer, but this is how I understand it)