This is the legal provision which prohibits Trump from legally using the military to build a wall. I don't believe that conservative judges will support the President in this legal violation.

343 U.S. 579 (1952)
YOUNGSTOWN SHEET & TUBE CO. ET AL.
v.
SAWYER.
No. 744.
Supreme Court of United States.

Argued May 12-13, 1952.
Decided June 2, 1952.
CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE DISTRICT OF COLUMBIA CIRCUIT.[*]

"...The President's power, if any, to issue the order must stem either from an act of Congress or from the Constitution itself. There is no statute that expressly authorizes the President to take possession of property as he did here. Nor is there any act of Congress to which our attention has been directed from which such a power can fairly be implied. Indeed, we do not understand the Government to rely on statutory authorization for this seizure. There are two statutes which do authorize the President 586*586 to take both personal and real property under certain conditions.[2] However, the Government admits that these conditions were not met and that the President's order was not rooted in either of the statutes. The Government refers to the seizure provisions of one of these statutes (§ 201 (b) of the Defense Production Act) as "much too cumbersome, involved, and time-consuming for the crisis which was at hand."

Moreover, the use of the seizure technique to solve labor disputes in order to prevent work stoppages was not only unauthorized by any congressional enactment; prior to this controversy, Congress had refused to adopt that method of settling labor disputes. When the Taft-Hartley Act was under consideration in 1947, Congress rejected an amendment which would have authorized such governmental seizures in cases of emergency.[3] Apparently it was thought that the technique of seizure, like that of compulsory arbitration, would interfere with the process of collective bargaining.[4] Consequently, the plan Congress adopted in that Act did not provide for seizure under any circumstances. Instead, the plan sought to bring about settlements by use of the customary devices of mediation, conciliation, investigation by boards of inquiry, and public reports. In some instances temporary injunctions were authorized to provide cooling-off periods. All this failing, unions were left free to strike after a secret vote by employees as to whether they wished to accept their employers' final settlement offer.[5]

587*587 It is clear that if the President had authority to issue the order he did, it must be found in some provision of the Constitution. And it is not claimed that express constitutional language grants this power to the President. The contention is that presidential power should be implied from the aggregate of his powers under the Constitution. Particular reliance is placed on provisions in Article II which say that "The executive Power shall be vested in a President . . ."; that "he shall take Care that the Laws be faithfully executed"; and that he "shall be Commander in Chief of the Army and Navy of the United States."

The order cannot properly be sustained as an exercise of the President's military power as Commander in Chief of the Armed Forces. The Government attempts to do so by citing a number of cases upholding broad powers in military commanders engaged in day-to-day fighting in a theater of war. Such cases need not concern us here. Even though "theater of war" be an expanding concept, we cannot with faithfulness to our constitutional system hold that the Commander in Chief of the Armed Forces has the ultimate power as such to take possession of private property in order to keep labor disputes from stopping production. This is a job for the Nation's lawmakers, not for its military authorities.

Nor can the seizure order be sustained because of the several constitutional provisions that grant executive power to the President. In the framework of our Constitution, the President's power to see that the laws are faithfully executed refutes the idea that he is to be a lawmaker. The Constitution limits his functions in the lawmaking process to the recommending of laws he thinks wise and the vetoing of laws he thinks bad. And the Constitution is neither silent nor equivocal about who shall make laws which the President is to execute. The 588*588 first section of the first article says that "All legislative Powers herein granted shall be vested in a Congress of the United States . . . ." After granting many powers to the Congress, Article I goes on to provide that Congress may "make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof."

The President's order does not direct that a congressional policy be executed in a manner prescribed by Congress —it directs that a presidential policy be executed in a manner prescribed by the President. The preamble of the order itself, like that of many statutes, sets out reasons why the President believes certain policies should be adopted, proclaims these policies as rules of conduct to be followed, and again, like a statute, authorizes a government official to promulgate additional rules and regulations consistent with the policy proclaimed and needed to carry that policy into execution. The power of Congress to adopt such public policies as those proclaimed by the order is beyond question. It can authorize the taking of private property for public use. It can make laws regulating the relationships between employers and employees, prescribing rules designed to settle labor disputes, and fixing wages and working conditions in certain fields of our economy. The Constitution does not subject this lawmaking power of Congress to presidential or military supervision or control.

It is said that other Presidents without congressional authority have taken possession of private business enterprises in order to settle labor disputes. But even if this be true, Congress has not thereby lost its exclusive constitutional authority to make laws necessary and proper to carry out the powers vested by the Constitution 589*589 "in the Government of the United States, or any Department or Officer thereof."

The Founders of this Nation entrusted the lawmaking power to the Congress alone in both good and bad times. It would do no good to recall the historical events, the fears of power and the hopes for freedom that lay behind their choice. Such a review would but confirm our holding that this seizure order cannot stand.

The judgment of the District Court is

Affirmed."