The United States has dozens of ongoing national emergencies. President Obama declared 13 national emergencies and President Clinton 17; it’s churlish and unfair not to let President Trump declare one too.
President Trump should declare some kind of national emergency shortage in his administration and find some more emergency-worthy issues. The Congress could find some itself and ask the President to recognize them officially as national emergencies.
An obvious candidate is the parts per million of carbon dioxide in the atmosphere being more than 500. Another is the lack of surplus drinking and irrigation water in the southwest.