Read the opinion. The point is that eligibility can never be determined before election day. Delay can and probably will move back to Texas before election day. That would make him eligible. He therefore cannot now or at any time prior to the election be declared ineligible. Because he is not. Reasonable minds cannot differ on this point.
The judge actually claims that Benkiser had
no evidence that Delay will not be an inhabitant on November 20th! I doubt the judge is correct. The judge's quote of Delay's letter to Benkiser includes a reference to the date.
Of course a Party can- and should- determine beforehand if someone will not be an inhabitant at such and such a date. Reasonable people, and the law, only ask evidence for a conclusion.
Kooks demand clairvoyance.
If Delay somehow managed not to ever clearly tell Benkiser that he will be an inhabitant of Virginia on the election (instead of just that he is presently an inhabitant) then he deserved to lose for such an error. But I seriously doubt that is the fact.