It seems to me, but perhaps I am wrong, that courts have already decided that he can enforce whtever law he wants and however he wants to enofrce them.
Because he has clearly not been faithfully executing laws, and he has never been held accountable for that, in fact in a number of instances, he has been changing laws at will, which he clearly has no authority to do, and he hasn’t been held acocuntable for that either by either a court or by the people who allegedly write those laws.
Obama is doing his version of the crime of “inciting a riot”.
In the earlier Arizona case there was a federal law that specifically denies the states the authority to enforce immigration laws without the approval of the Feds.
There is no law authorizing what Obama is doing now.
It is based on a concept- prosecutorial discretion- which may, or may not, be supported by a court.
True, heretofore he hasn't been challenged. But I believe this is the first time he's been challenged by the states on "prosecutorial discretion". The earlier Arizona case was decided on a separation of powers issue -- the states having no constitutional role in immigration enforcement.
Separately, Boehner's lawsuit has now been filed, too, challenging the President's usurpation of Congressional legislative powers.
We'll just have to wait and see how the court challenges play out.