The Open Door Policy was designed as a way for the United States to further options: 1) its trade interests. 2) its desires to annex foreign nations. 3) international diplomacy. 4) the establishment of democratic governments.
The Open Door Policy was designed as a way for the United States to further "1) its trade interests", since it was primarily aimed towards China--keeping China open to trade with the US and other European nations on a "fair" basis.
