I think it depends on what is meant by "fraud". I do not think it is difficult at all to prove, to any objective reviewer, that many ballots were invalid and generated and cast by other than legal voters; and vote tabulations were manipulated by manual and programmed computer intervention; and in total more than sufficient to change the outcome of the 2020 US presidential election. Proving "who" is responsible for that , their intent and premeditation is much more difficult, particularly within the time frame to prevent an illegitimate inauguration. However, if the election results are not legitimate then they should be thrown out regardless of the details of and parties involved in producing the illegitimate results. The constitutional republic and government of, by, and for the people depend on it.
I heard an analogy with the bending of light. Paraphrased it said that astronomical observation of the bending of light
infers the presence of a black hole (infinite mass). in fact the bending of light
confirms the presence of infinite mass or its energy equivalent. In the case of the subject election, mathematically improbable (to the level of practical impossibility) vote totals and tabulation irregularities (subtraction, fractional, vertical "curves", 100k + vote dumps for one candidate)
prove that the current vote totals are invalid in quantity more than enough to reverse the election.
Our founders pledged their lives, fortunes and sacred honor. In short order we shall find out what we pledge.
I hate tu. It's in my blood.