[4][5] Before 1800, the main factors in German-American relations were very large movements of immigrants from Germany to American states (especially Pennsylvania, the Midwest, and central Texas) throughout the 18th and the 19th centuries.

A crisis in 1898, when Germany and the United States disputed over who should take control, was resolved with the Tripartite Convention in 1899 when both nations divided up Samoa between them to end the conflict.

Germany agreed to US demands to stop such attacks but reversed its position in early 1917 to win the war quickly since it mistakenly thought that the US military was too weak to play a decisive role.

[22] In 1937, during the Hindenburg's 63rd voyage, which had long been the preferred mode of rapid transatlantic travel between the United States and Germany, a tragic incident occurred as it met its unfortunate end in a catastrophic crash in Lakehurst, New Jersey, USA.

In the wake of this devastating event, rumors and speculations circulated among some German citizens, suggesting the possibility of sabotage orchestrated by elements within the United States government.

[27] Upon becoming the secretary of education of Massachusetts in 1837, Horace Mann (1796–1859) worked to create a statewide system of professional teachers, based on the Prussian model of "common schools."

They returned with PhDs and built research-oriented universities based on the German model, such as Cornell, Johns Hopkins, Chicago and Stanford, and upgraded established schools like Harvard, Columbia and Wisconsin.

What existed ran between the American ports of Baltimore, Norfolk, and Philadelphia and the old Hanseatic League free cities of Bremen, Hamburg, and Lübeck grew steadily.

The American secretary of state (foreign minister) said in 1835 that "not a single point of controversy exists between the two countries calling for adjustment; and that their commercial intercourse, based upon treaty stipulations, is conducted upon those liberal and enlightened principles of reciprocity... which are gradually making their way against the narrow prejudices and blighting influences of the prohibitive system.

German men who immigrated to the U.S. then returned home were liable for military service, but that was a minor irritant and was largely resolved by treaties negotiated by American minister George Bancroft in 1868.

[51] In the 1880s, ten European countries (Germany, Italy, Portugal, Greece, Spain, France, Austria-Hungary, the Ottoman Empire, Romania, and Denmark) imposed a ban on importation of American pork.

European farmers were angry at cheap American food overrunning their home markets for wheat, pork, and beef; demanded for their governments to fight back; and called for a boycott.

Chancellor Bismarck took a hard line, rejected the pro-trade German businessmen, and refused to join in scientific studies proposed by President Chester A. Arthur.

President Harrison used his Agriculture Secretary Jeremiah McLain Rusk to threaten Berlin with retaliation by initiating an embargo against Germany's popular beet sugar.

[58] The issue emerged in 1887 when the Germans tried to establish control over the island chain and President Cleveland responded by sending three naval vessels to defend the Samoan government.

Berlin realized the resumption of unrestricted submarine warfare almost certainly meant war with the United States, but it calculated that the small American military would take years to mobilize and arrive, when Germany would have already won.

[77] Wilson called on Congress to declare war on Germany in April 1917 in order to make the world "safe for democracy" and defeat militarism and autocracy.

At the Paris Peace Conference of 1919, Wilson used his enormous prestige and co-operated with British Prime Minister David Lloyd George to block some of the harshest French demands against Germany in the Treaty of Versailles.

Key players included officials Charles G. Dawes and Owen D. Young, Wall Street bankers, the Federal Reserve Bank of New York, and the first postwar ambassador, Alanson B. Houghton (1922–1925).

The American musical elite, according to Geoffrey S. Cahn, was sharply negative toward the atonal and serial compositions of Arnold Schoenberg, Alban Berg, and Paul Hindemith.

Germany's effort to incorporate any major military actions into the European Union's slowly-progressing Common Security and Defence Policy did not meet the expectations of the U.S. during the Gulf War of 1990–1991.

[122] In response to the 2013 mass surveillance disclosures, in which it was revealed that the NSA may have wiretapped major German institutions, including the phone line of Chancellor Merkel,[123] Germany cancelled the 1968 intelligence sharing agreement with the US and UK.

A survey conducted on behalf of the German embassy in 2007 showed that Americans continued to regard Germany's failure to support the war in Iraq as the main irritant in relations between the two nations.

In March 2019, Trump was reportedly drafting a demand several countries, including Germany, to pay the United States 150% of the cost of the American troops deployed on their soil.

In 2013, the global surveillance and espionage affair revealed that the American NSA had eavesdropped on and spied on almost all top German politicians, including Chancellor Angela Merkel.

[174] In 2019 the United States Senate[175] announced intention of passing controversial legislation which threatened to place sanctions on German or European Union companies which work to complete a petrol-chemical pipeline between Germany and Russia.

It is on the historic axis between the White House and the Washington Monument on the National Mall, the garden borders Constitution Avenue between 15th and 17th Streets, where an estimated seven million visitors pass each year.

[179] Following the Nazi rise to power in 1933, and in particular the passing of the Law for the Restoration of the Professional Civil Service which removed opponents and persons with one Jewish grandparent from government positions (including academia), hundreds of physicists and other academics fled Germany and many came to the United States.

[180][181] After WWII and during the Cold War, Operation Paperclip was a secret United States Joint Intelligence Objectives Agency (JIOA) program in which more than 1,600 German scientists, engineers, and technicians (many of whom were formerly registered members of the Nazi Party and some of whom had leadership roles in the Nazi Party), including Wernher von Braun's rocket team, were recruited and brought to the United States for government employment from post-Nazi Germany.

[182][183] Wernher von Braun, who built the German V-2 rockets, and his team of scientists came to the United States and were central in building the American space exploration program.