Declaration by the United Nations: 1 January 1942

     The United Nations Declaration, signed originally by the representatives of the United States of America, the United Kingdom of Great Britain and Northern Ireland, the Republic of China and the Soviet Union, served as a uniting factor for all the allied countries against Germany and Japan. Signed by the 'Big Four' on the first day of the year 1942, it was signed by twenty two other countries on the next day. 

     The declaration united these 26 countries in the common war against Germany and Japan. Furthermore, it forbade these countries from making separate peace. The latter clause was a simple reiteration of the reforms that were to be followed post- 1919 after the first great war. Now, the allied forces had one and only on purpose; to defeat the Axis powers in order to safeguard its own peoples. 

     The principles of the declaration were based on the principles put down in the Atlantic Charter. It is clearly stated in the text that the signatories of the declaration have 'subscribed to a common program of purposes and principles embodied in the Joint Declaration of the President of the United States of America and the Prime Minister of the United Kingdom of Great Britain and Northern Ireland dated August 14, 1941, known as the Atlantic Charter.' 

     At the San Francisco Conference, three years later, only the nations that had declared war on Germany and Japan were invited to take part in order to unite only those with similar ideologies. The declaration can be credited with bringing together all countries that had the same mission into one joint force that proved to be fatal for the enemy. 

For further reading: 

The Declaration by United Nations (http://www.un.org/en/aboutun/history/declaration.shtml)

A Decade of American Foreign Policy: Declaration by the United Nations, January 1, 1942 (http://avalon.law.yale.edu/20th_century/decade03.asp)