In World War II, the Allies appeased Hitler when he began invading surrounding countries and allowed him to gain power before war was declared on Germany, leading to a horrific and drawn out war. Truman did not want to make the same mistake and allow North Korea to cause immense damage due to his failure to act soon enough.
President Harry Truman had to decide whether to use the newly-built atomic bomb against the Japanese. He finally decided to use it to protect American lives that would be lost if Japan was invaded.
Germany invaded Ethiopia
He could have invaded Japan. But this would have cost more American lives and would have taken a long time.
Germany invaded Poland
Mongol invaded Korea around 1231.
No president invaded the nazis in 1939
Russia was invaded by Germany..............................
Benito Juarez (1806-1872) was such president.
Reagan
Ronald Reagan
Woodrow Wilson
Saddam Hussein was the President of Iraq who invaded Iran during the Iran-Iraq War.
President George H.W. Bush.
Franklin D. Roosevelt
Also known as "Desert storm" Kuwait was invaded by Iraq.
As soon as South Korea was invaded in June 1950.
George H. W. Bush