Trying to configure the logic of Trump support in a formal way, I began with a simple syllogism.
1. Trump won the election. Official vote counts show Biden with 7 million more votes. Therefore the official vote counts are wrong.
This captures the essence of the position, but it is not really a valid deductive structure. The major premise is without doubt the dominant premise of Trump's supporters, but its form is more appropriate to the minor premise because it is a specific instance. Similarly the minor premise doesn't instantiate a specific case of the major premise. So I tried again.
2a. To win an election a candidate must get more votes. Trump won the election. Therefore Trump got more votes.
2b. To win an election a candidate must get more votes. Official vote counts show Biden got 7 million more votes. Therefore Biden won the election.
This is better structurally and we have also formalized the dispute. It is better structurally because the major premise is general and the minor premises are specific cases.
Putting them together we have a clear contradiction which can be analyzed. Since both deductions share the major premise, there is no dispute here about how to win an election. The contradiction could arise from faulty deduction but that is not the case here. Thus we need to focus on the minor premises. The contradiction can be explained if the one of minor premises is false since in that case the conclusion is also false -- or rather the deduction leading to that conclusion is a false deduction and its conclusion is mere speculation.
But which of these minor premises is false? This syllogism seems to express the point of view of deluded insurrectionists:
3. Either "Trump won the election" is false or "Biden got more votes" is false. "Trump won the election" is not false. Therefore "Biden got more votes" is false.
This is a perfectly valid deduction. It is not a great leap of logic however as it basically says that if you assume Trump won the election (minor premise) then you can't also assume Trump lost the election.
What's missing in this examination of the premises is actual reality. The dispute is not a dispute about logical deduction but about the truth of the minor premises. If the premise is false, the deduction is worthless however valid it may be in form. This recasts the argument completely.
Formal logic lets us observe the contradiction but by itself logic does not allow us to resolve the contradiction. Either "Trump won the election" is false or "Biden got more votes" is false. But which one? Logically the propositions are each well formed and meaningful. This is a conundrum through which a large minority of citizens are presently unable find a path.
Formal logic is a really cool intellectual toy but as a practical tool it has some drawbacks. The first and most annoying is that every time someone comes up with a better way to express logical reasoning the logicians take it over and hedge it around with arcane symbology and obscure jargon with what seems to be a desire to withhold good toys from ordinary girls and boys.
Formal logic is helpful in clarifying contradictions and demonstrating logical consistency. A second drawback is that it isn't particularly helpful at deriving consistent theories in the first place. This means that usually we use other means and methods to develop an idea. Formal logic can be used after the fact to verify the result, an add-on and not an intrinsic part of the process.
A third drawback is that building a model in formal logic is really hard. It takes a lot of skill and creativity to be successful. There is no straightforward and obvious path from informal reasoning into a formal model of the same idea. The absence of a validated model in formal logic therefore conveys no information about a proposal; it could be because the idea is not valid or it could be that the proposer did not have the skills to create the model or that no one attempted to build a logical model of the proposal.