Filed on February 15, 2019, this case challenged the declaration of a national emergency issued by President Trump that same day, the invocation of emergency powers stemming from that declaration, the resulting agency actions taken or directed to be taken in the exercise of those claimed emergency powers, and the expenditure of funds to construct a border wall in the absence of the constitutionally required appropriations and statutory authorization for such expenditures. Rather than responding to an emergency requiring immediate action, the declaration addresses a long-running disagreement between the President and Congress about whether to build a wall along the southwestern border. Congress refused to appropriate funds for that purpose. However, under our Constitution, built on the principle of separation of powers, a disagreement between the President and Congress about how to spend money does not constitute an emergency authorizing unilateral executive action. The declaration and the planned expenditure of Department of Defense funds for construction of the wall exceed President Trump’s authority under the National Emergencies Act, other statutes invoked by the President as authority to fund the wall, and the Constitution. The invocation of emergency powers and exercise of those powers, and the diversion of funds to build a wall, are thus contrary to law.