The United States has had diplomatic relations with the nation of Germany under its various forms of governments and leaders since 1871, and its principal predecessor nation, the Kingdom of Prussia, since 1835. These relations were broken twice (during the First World War 1917 to 1921, under 28th President Woodrow Wilson), and again during the Second World War from 1941 to 1955, at first under 32nd President Franklin D. Roosevelt, continuing under 33rd President Harry S. Truman and 34th – Dwight D. Eisenhower), while Germany (first as the German Empire (Imperial Germany), 1871–1918, later under Kaiser / German Emperor Wilhelm II (1859–1941, reigned 1888–1918), and second as Nazi Germany (National Socialist Germany, 1933–1945), under the regime of dictator / Fuhrer Adolf Hitler,1889–1945), when there was a state of war with the United States and for a continuation interval afterwards, following the 1918 Armistice or the 1945 Surrender and halting of military combat operations.
Prior to 1835, the United States and the Kingdom of Prussia in Central and Eastern Europe, had recognized one another – but did not exchange any diplomatic representatives, except for a brief period at the turn of the 18th-to-19th centuries, when minister plenipotentiary John Quincy Adams (1767–1848, future 6th U.S. President, 1825–1829) was accredited to the Prussian court in Berlin, heading the U.S. Legation there, during the reigns of two monarchs, Kings of Prussia of Frederick William II (1747–1797, reigned 1786–1797) and King Frederick William III (1770–1840, reigned 1797–1840). American Minister Adams was also accredited to and visited Scandinavia sailing across the Baltic Sea to the nearby Kingdom of Sweden in Stockholm, with U.S. Legations at both posts from 1797 to 1801, during the administration of American second president of John Adams (1735–1826, served 1797–1801), who happened to be his father, and briefly before returning to America, during the beginning of subsequent administration of third President Thomas Jefferson (1743–1826, served 1801–1809). During J.Q, Adams tenure in Prussia / Sweden, he re-negotiated and renewed the earlier Treaty of Amity and Commerce (Prussia-United States) of September 1785 (ratified a decade before by the old Confederation Congress and former presiding / executive officer President of the United States in Congress Assembled under previous governing document Articles of Confederation and Perpetual Union of 1781–1789), renewed by Ambassador (Minister) Adams in 1799.
