The United States of America shouldn't go to war on Mexico because America has too much money in Mexico to go to war. Also in doing so America will lose an asset that they have during wars.
Following the American Revolution, the Confederation Congress was unable to resolve the nation’s economic crisis because it could not "tax the states", which was required if enough revenue was to be raised to pay back the war debt.
There were many reasons. The country was in extreme poverty, there was starvation everywhere and people were dying in misery. They wanted to change the imperialistic rule and impose their own bolshevik rule. People also wanted to end their participation in the war which is one of the first things that happened after the revolution. The communists left the war before the war ended.
He believed that Germany was trying to develop one
Ronald Reagan and Mikhail Gorbachev worked together to improve the relations between the US and USSR.
Gorbachev's policies surrounding Glasnost allowed for a more democratic Russia (and also eventually led to the collapse of the Soviets).