The law can only be enforced when US still have the influence and military might.
As soon as US lose that influence, no one will care what US want.
A law can only be enforced when the people chose to allow it to enforced.
Anyone can decide to not follow the law, and nothing can stop them from the choice to not follow a law.
What can be done is punishment for not following the law, after the fact. Punishment is only repercussion, and cannot stop someone from committing the crime before they do it.
That said, you can now be thrown into prison indefinitely for being a "suspected" terrorist. Still, that's really just the government breaking the law. The government, in this case, is just choosing to not be enforced by these laws.