Trump's claim that he declassified the documents would come after he's indictedvwich is extremely unlikely.
It would be legal malpractice for his attorneys to swear to it under oath now. Not to mention absurd since They are not fact witnesses.
The lawyers don't have to swear anything. They simply need to deliver a signed affidavit from Trump, who is the ONLY fact witness.
As for legal malpractice. I find that an interesting argument his lawyer made. It's interesting because it makes little sense.
In what way would providing evidence in a civil court of a claim that you are PUBLICLY making hinder the legal defence in a criminal court?
In fact, the lack of evidence provided in court has already made his way in a ruling of the 11th District as a reason to side with the prosecution granting them a partial stay.
It was the lawyers making a strained argument to not have to provide a knowingly false statement to the judge in my opinion.
You are kind of right though. It is true that providing such a statement in court would be legal malpractice. Making such a ridiculous and probably easily refuted claim in court would subject their client to possibly perjury charges and themselves to all kinds of sanctions. From remedial training, to disarmament, and even possibly criminal charges.
Something that has all happened to lawyers representing Trump in the recent past. Which should tell you something by the way