One reason may be that a Declaration of War triggers 170 statutes http://www.ndu.edu/...
which give the President and the Secretary of Defense immense power.
These powers cover civilian and military federal employees (both extending dates of service and calling up reserves); aliens who attempt to avoid military service (revoke or deny visas and/or naturalization) and any citizen who joins hostile armed forces shall lose his nationality.
The Federal Energy Regulatory Commission can reorder the use of all energy sources.
The TVA (Tennessee Valey Authority) can be placed under government control to "manufacture explosives or for other war purposes".
Other areas affected during war Imports, International claims, Accounting and contracts with DOD, GSA, and the Department of Energy.
The President can suspend regulations governing NOAA, ocean dumping of pollution by war ships, and by public vessels of potentially infectious medical waste.
The President can lift the caps on the number of armed forces and civilian employees in Defense agencies, and can extend their service for the length of the war. He can also "arm, have armed, or allow to be armed" any watercraft or air craft used as a means of transportation "on, over, or under water".
The President can declare the commissioned corp of the Public Health Service to be a military service subject to the Uniform Code of Military Justice; and cause to be apprehended individuals believed to be infected with a disease that is the "probable source of infection to members of the armed forces of the United States or to individuals engaged in the production or transportation of arms, munitions, ships, food, clothing, or other supplies for the armed forces". Comprehensive!
Controls can be increased on Nuclear Energy, Public Lands, Natural Resources (including suspension of oil leases and/or right of first refusal to purchase any "mineral" at market prices).
Exemption from the military service can be granted to personnel engaged in shipping and other fields, and controls can be instituted on shipping and the ownership of shipyards.
Controls can be instituted on communications, railroads, and harbors.
All of the above can also be triggered by a presidential Declaration of a National Emergency. In the case of a declaration of a National Emergency, 50 more statutes may come into effect controlling:
Federal Employees, Agriculture, the Customs Service, Student Aid, Foreign Relations, NOAA, the Red Cross, Veterans Affairs, Real Property and Contracts, the Public Health Service, relocation of persons displaced from their dwelling, Airports, and Defense Contracts.
These drastic measures are meant for what has in the past been considered an all out war, not for limited hostilites. A Declaration of War would place the country and it's citizens on a true war footing. I'm old enough to remember blackouts, gas and sugar rationing, and the draft. I don't want Congress issuing a Declaration of War unless we are in REAL war. And I don't want a National Emergency declared unless it IS a national emergency.
