National Emergency - a bad idea?

https://www.dailywire.com/news/41987/trumps-considering-declaring-national-emergency-ben-shapiro

“In the event of a declaration of war or the declaration by the President of a national emergency in accordance with the National Emergencies Act,” undertake “military construction projects, and may authorize the Secretaries of the military departments to undertake military construction projects, not otherwise authorized by law that are necessary to support such use of the armed forces.” It would be a serious stretch to suggest that military necessity dictates the overruling of Congressional powers in this case – and it sets the precedent that the executive would presumably try to declare a national emergency to redirect already-allocated defense funding to pet projects on a routine basis. Imagine Elizabeth Warren declaring a “green national emergency” and then authorizing the military to shutter coal plants, as Erick Erickson has suggested.

As David French points out at National Review, President Truman attempted to do exactly that with regard to steel works in the United States during the Korean War, and was rejected by the Supreme Court, which declared, “The order cannot properly be sustained as an exercise of the President’s military power as Commander in Chief of the Armed Forces.”