Pearl Harbor push the US into the war against the axis powers
Depression of the 30's.
The US helped France in world war 1 with submarines in the Atlantic.
Basically, both World War 1and World War 2 helped the US recover from the current depression at the time. As some people say, the US was forged by war.
They helped the Allies win the war.
'Russia' was too busy to involve US into a World War I as there was a revolution in Russia at that time.
Russia pulled out of the war, so the Allies needed help. The Russian Revolution weakened the Allied war effort.
World War 2
NAVAJO
FDR .
US Aid to Israel in the Arab-Israeli War of 1973 helped Israel to reverse the tide of that war and push back the invading Arab armies.
Winston Churchill helped make the world a better place because he helped to give us freedom and he helped us win the second world war.