Now I didn't think that you'd be so hypocritical as to apply this only to federal law. I thought the concept of due process applies to both federal and state laws.
You both don't fail to disappoint when it comes to legal analysis.
No, it's a fairly old principle, which is that the federal government shouldn't exceed the powers assigned to it. There's another relatively old principle which is that if you're going to convict someone for intent to do such-and-such a thing, you should have to prove to the jury that his actions actually did betray such an intent. The newer principle that the government seems to be operating on is that it can just assume that intent exists from just a few arbitrary facts.
If a state legislature wanted to pass a law stating that automobiles could only be sold on the day of the week corresponding to their color (e.g. blue or yellow cars on Sunday, red or orange cars on Monday, green cars on Tuesday, etc.) it would be within its power to do that. The legislature would be under no obligation to explain the reason for the law (indeed, there may not be one).
In cases where the reason for a law is clear but it shouldn't be applicable in a particular case, a person should have the opportunity to argue that before a jury (state as well as federal) but the burden would be higher. Still, in some cases I think the case could be made convincingly.
For example, if someone who was charged with DUI wanted to argue that (1) their vehicle was parked, and (2) there was no evidence they made any attempt to move it while intoxicated, I think a sensible jury would likely find that even if the person technically had "control" of their vehicle, and even if the engine was running 'cos it was freezing outside, the person's conduct not only posed no risk to anyone, but should be considered commendable compared with the only practical alternative.