I have no doubt that this, or any other possible, Supreme Court would uphold Ex parte Milligan 9-0 in less than ten minutes.
If you need to look up ex parte Milligan, then you should not be posting about "martial law".
The Supreme Court has already folded. President Trump either takes this fight to the bitter end or he quits.
If martial law is not enacted and Joe Biden is inaugurated on January 20, then we will know that Trump is a quitter.