What Law Did He Adjudicate?

District Judge John Bates has ordered the government to restart the Deferred Action for Childhood Arrivals (DACA) program.  The DACA law was never passed.  Congress declined to pass the DREAM Act so President Obama issued an executive order for the government to enforce immigration laws as if Congress had passed a watered-down DREAM Act.  Let us ignore the legality of the president enforcing a law that was not passed and accept that the executive order was a temporary workaround.  However, executive orders are entirely under the discretion of the sitting president.  Obama countermanded many Bush executive orders and Trump can do the same with Obama's executive orders.  The president is not bound by the executive actions of his predecessors.  There is no law for a judge to rule upon.  He is ruling upon discretion that is completely in the hands of the executive branch.  Unless Congress has passed a law that changed the discretion since Obama implemented DACA, the court has no role if Trump used that same discretion to eliminate the program.  This is obviously judicial overreach and will clearly be overturned on appeal.  This is judicial activism.