"Emergency does not create power. Emergency does not increase granted power or remove or diminish the restrictions imposed upon power granted or reserved. The Constitution was adopted in a period of grave emergency. Its grants of power to the federal government and its limitations of the power of the States were determined in the light of emergency, and they are not altered by emergency." -- Chief Justice Charles Evans Hughes (1862-1948)

This week, the United States Senate will take a historic vote known as a negation, a statutory procedure whereby Congress nullifies an act of the president. The negation vote is authorized by the National Emergencies Act of 1976, which was written to permit the president to streamline government during an unforeseen crisis.

The act itself fails to define what constitutes an emergency, but the courts -- as is their job where a law is ambiguous -- have generally defined an emergency as a sudden and imminent threat to life, liberty and property that cannot be addressed by the exercise of ordinary government powers.

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When Hurricane Katrina devastated New Orleans, President George W. Bush declared a state of emergency. That declaration enabled him to move government assets and materials to suffering folks without regard to environmental laws, public bidding laws or even local speed limits. But it did not permit him to spend money that Congress had not authorized, nor could he as president exercise any powers that the Constitution delegated to Congress.

President Donald Trump, in his recent declaration of national emergency at the U.S.-Mexico border, ordered the departments of Defense and Homeland Security to spend unused but unauthorized money in their budgets on building a 55-mile steel barrier -- "a big, beautiful wall" -- along a portion of that border. Because Congress has expressly and explicitly declined to authorize the funds for the construction of such a barrier, we have a constitutional conflict on our hands.

The conflict is more acute than just a difference of opinion. It is an issue for Trump of fidelity to his oath of office. Several of the statutes that Trump will be violating by spending unauthorized money on the border barrier he himself signed into law. In the presidential oath, the president agrees to enforce federal laws "faithfully" -- whether he agrees with them or not.

Can the Congress amend the Constitution? Can it cede to the president powers that the Constitution has delegated to Congress? Every time the courts have addressed these questions, they have answered with a resounding NO.

The issue of whether the status of matters at the southern border rises to the level of emergency will soon be decided by a federal court. It will rule if in the present situation there is an A) sudden, B) unanticipated and C) true threat to life, liberty or property that D) cannot be addressed by the ordinary employment of government assets. If a court decides that any of the A through D factors is not present, that is the end of the inquiry; the court will enjoin the enforcement of Trump's declaration because it does not fit within the definition of an emergency.

But if a court agrees with the president -- that the monthslong mass movement of migrants from Mexico to Texas is an emergency that cannot be addressed by ordinary means -- it must then address the constitutional issues. Here, the law is clear.

Under the Constitution, only Congress gets to decide how money from the federal treasury shall be spent. When the president has asked for funds -- here, to condemn private property and build the barrier -- and Congress has said no, he cannot legally go out and spend the funds anyway. Some have argued that Congress has given away some of its powers to appropriate funds to the president during prior emergencies. And some have argued that the existence of an emergency gives new powers to the president. Such arguments betray gross ignorance of the Constitution.

Can the Congress amend the Constitution? The short answer to this is NO. Only three-quarters of the states can amend the Constitution. Yet, for generations, Congress and the president have engaged in a subtle amendment by consent. This has generally occurred when presidents have started wars -- a congressional function -- and Congress has looked the other way. Without judicial intervention -- often nearly impossible because only a member of Congress would have standing to sue -- Congress and presidents get away with this.

This amendment by consent is at the core of President Trump's argument. He and his Republican colleagues in Congress have argued that Congress has given all presidents since 1976 new powers in emergencies. This is not possible under our system of constitutional government, even if all concerned did look the other way with a wink and a nod. Presidential power comes only from the Constitution, not from Congress.

In an ironic sense, those of us who believe that the Constitution means what it says are grateful to President Trump for teeing up this issue, expecting a judicial injunction. But no member of Congress can be faithful to her or his oath of office and still support Trump's view of extraconstitutional powers.

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This week, the Senate can follow the House in voting to prevent President Trump from getting away with this. The price of him doing so far exceeds the construction costs of a border barrier. When a president exercises extraconstitutional power, he violates his oath to be faithful to the Constitution and he strikes at the core principle of the separation of powers. Such a strike irreparably undermines the basic protection of freedom in America itself.

In this case, the freedom being undermined is the right of the people to a government that obeys its own laws. Emergency does not create presidential power; only the Constitution does.

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