There is no justice

So, let me see if I've got this right.

If someone is lawfully convicted in a US court of law, having been given every right and opportunity to defend himself, yet dies before he can appeal, his conviction is vacated. OK, I can accept that, even for Ken Lay.
But, now the President can decide to arrest someone without presenting any evidence whatsoever, there can be a trial without the defendant even seeing the evidence against him, and he can be executed. Period.

Ummmm, something doesn't seem right here.