There is no doubt that Trump’s mania about his wall, which has been thwarted by Mexico, the democrats and enough republicans to stop it when they had control of both the House and the Senate, is now an emergency for his Presidency. The question is, can this be a real national emergency for America? The answer must surely be no. A national emergency is not a device to bypass the democratic will of Congress. It is a power to be used in a pressing national crisis when extra resources have to be deployed faster than the proper due process can deliver them. It is not put there so that a thwarted President can ignore the structures of democracy.
Trump’s declaration will be challenged in Court and may well end up in the Supreme Court. If it finds that the Constitution can be interpreted to allow this misuse of executive power, only one thing is certain thereafter. At some point in the future America will live very much to regret it.