Here are the various credible legal defenses for Trump that I'm aware of. All of them are terrible. There is no Perry Mason-like defense of exposing the real killer and exonerating defendant Trump. Trump's defenses are all about suppressing evidence, claiming Trump is a "victim", and asserting some special unique rights that only Trump should be granted.
1. Selective prosecution. That's the whataboutism defense. It basically is saying somebody else (Hillary, Joe Biden, Mike Pence) also did something similar. Trump wouldn't return "my boxes" when asked nicely by the government. The other pols didn't put up a fuss like Trump and cooperated. The problem with the "selective" claim is that is many lower level and not-so famous people have been sentenced to lengthy prison terms for doing the same thing as Trump. If Trump were NOT prosecuted that would be selective.
2. The notes by Trump defense lawyer Corcoran should be excluded. Corcoran's notes have been allowed as evidence because of the crime-fraud exception. Excluding that evidence is not an argument that Trump is innocent. It's that Trump doesn't want the jury to see documentation of his guilt.
3. Trump declassified them before leaving office. He has said he can declassify with his mind. This doesn't pass the laugh test. He is also on tape admitting he cannot declassify as an ex-president.
4. Prosecutorial misconduct. Supposedly that happened during the grand jury stage. That ship has already sailed. The indictment has already been issued. Even if it were the case (there is no reason to think that it did), the guilty attorneys might have be disciplined; but the indictment is not thrown out.
5. Trump or some other GOP candidate should be elected president and pardon Trump That's not an effort to prove he is innocent. It's just admitting that Trump is guilty. It also is an attack on the jury saying that they cannot render a fair and honest verdict, even though it's in Trump's preferred venue with Trump's preferred judge.