Although the treaty was a challenge during the First World War, its conditions were not changed. Similar problems arose before the Second World War, but Foreign Minister Cordell Hull wanted to maintain the agreement because of its historical importance. In 1939 and 1940, Canada and the United States agreed to interpret the treaty so that weapons would be installed in the Great Lakes, but would not be passable until the ships had left the lakes. In 1942, the United States, which had gone to war and allied with Canada, successfully proposed to install and test weapons in the lakes until the end of the war. In 1946, following discussions in the Permanent Joint Defence Council, Canada also proposed to interpret the agreement to allow the use of ships for training purposes when each country informs the other country.  An Ontario Heritage Trust plaque in Kingston, Ontario, recognizes the Rush Bagot Agreement (44-13`48`N 76-27-59`W / 44.22989 N 76.466292-W / 44.229894; -76.4662922). A commemorative plaque is also located on the former site of the British envoy in Washington, D.C., D.C. (38-54`13.N 77-3`8.4`W / 38.903806 N 77.05233-W / 38.903806; -77.052333), where the agreement was negotiated. A monument is also located on the site of the Old Fort Niagara (43-15`N 79-03`49`W / 43.263347 N 79.063719 W / 43.263347; -79.063719), reliefs of Rush and Bagot, as well as the words of the treaty.  The rush bagot pact was an agreement between the United States and Great Britain to eliminate their fleets from the Great Lakes, with the exception of small patrol vessels. The 1818 convention established the border between the territory of Missouri in the United States and British North America (later Canada) at the forty-ninth parallel. Both agreements reflected the easing of diplomatic tensions that led to the War of 1812 and marked the beginning of Anglo-American cooperation.
Mr. Bagot met informally with Foreign Affairs Minister James Monroe and finally reached an agreement with his successor, Current Minister Richard Rush. The agreement limited military navigation on the Great Lakes to one or two ships per country on each sea. The U.S. Senate ratified the agreement on April 28, 1818. The British government felt that an exchange of diplomatic letters between Rush and Bagot was sufficient to make the agreement effective.