What happens if presidential elections were not fair (in some states)?
GovTrack, in response to,
“He commits to a peaceful transfer, as long as it’s a fair election.”
— Mark Meadows, chief of staff to President Trump and former representative, on the end of President Trump’s term as president. Sep 25, 2020
opines that,
The United States Constitution does not say that elections must be fair. [...]
This is a country of laws first, fairness second. We follow laws today and make them fair tomorrow. [...]
On January 20, 2021 at noon, the current term of the President of the United States will end — fair or not. [...]
Our mission cannot be fulfilled when faithful execution of the law is replaced with an ultimatum for something that does not and has never existed.
Can a court decide to repeat the election?
No, the date of the election is fixed by law and state laws will determine what actions may be taken with regard to electors for president and vice-president.
However, the courts are already involved state election laws in other ways.
Federal court overturns Texas' repeal of straight ticket voting option, 09/25/20
A federal judge issued a ruling late Friday blocking Texas from eliminating straight-ticket voting as an option for the state’s voters in this year’s election.
Marmolejo ruled that removing the option would “cause irreparable injury” to voters “by creating mass lines at the polls and increasing the amount of time voters are exposed to COVID-19” and “likely to cause confusion among voters.”
Most states do not offer a straight-ticket option, but the practice has become popular in Texas, which notoriously has long ballots.
State Republicans passed a law in 2017 barring straight-ticket voting, arguing that removing the option would press voters to make more informed decisions about for whom they cast their ballots. An amendment delayed its implementation until the 2020 general election.
Democrats sued Texas in March over the 2017 law’s implementation and were swift to hail Friday's ruling as a win against voter suppression.
Republicans argue that more informed voters is fair.
Democrats argue the allowing a straight Democrat vote is fair.
A federal judge ruled that delaying the implementation of a duly enacted law is fair.
There are no standards, nor any requirements, for fairness — merely laws to be enforced.
What else could be the result?
After all is said and done, Democrats and Republicans will take positions and argue until the next election. Maybe they will compromise on some issues, maybe not.