If Obama is providing a service not authorized by existing law, then he is breaking the law.
If Obama is simply not providing a service authorized by existing law, then he is simply failing to enforce that law.
Doing nothing is not a usurpation, and I remind you he is not the only player on the field. We have state & local governments capable of enforcing laws as well should they consent to them.
“We have state & local governments capable of enforcing laws as well should they consent to them.”
Exactly right. Just like the feds used to enforce dope growing laws in CA when the locals wouldn’t. That game works both ways.