Congress...chooses not to enforce it? You're talking about Congress, commonly known as the executive branch of the triune government, which enforces the laws?
It's at times like these I'm reminded of the saying...that fog is a sign of merging timelines.
The answer is that the Constitution give Congress abilities like impeachment specifically to give them the ability to apply pressure and "enforce" that the executive branch does what it is entrusted to do.
The exact same situation applies to police. Surely you understand that it is possible for police officers to break the law even though they are technically also the people responsible for enforcing it?
See this: https://www.wdrb.com/us-capitol-in-fog/image_571cd9fc-ca8b-1...
What you're looking at is the probability of the US Capitol being in a particular place. It's a common misconception that fog makes things look blurry, but you're seeing the effect of the average probability of it being there at all, given the many possibilities in alternate time tracks. It is blurry. Never mind what might be going on inside.
People who wander into fog often come out into a different world, but generally their memories adjust...not always though.