As a candidate the current president had every right to attack the Affordable Care Act (Obamacare), as president he had every right to try to "repeal & replace' that law, but now that those efforts have collapsed he cannot sabotage or defund that duly enacted law.  In our Constitution Article II establishes the presidency and defines its duties and responsibilities, including (among the last): "...he shall take Care that the Laws be faithfully executed,..."
      He might also consider ending his "bearing false witness", perjury in our Constitutions language if for no other reason than most folks see thru the lies.