Answer:
Slavery was so profitable, it sprouted more millionaires per capita in the Mississippi River valley than anywhere in the nation. With cash crops of tobacco, cotton and sugar cane, America's southern states became the economic engine of the burgeoning nation.
Secretary of State Marshall suggested his plan to help rebuild European economies after World War as a way of staving off political instability and poverty conditions, which would become breeding grounds for governments that would go against freedom.
Explanation/context:
The "Marshall Plan" was named after the man who then was US Secretary of State, George C. Marshall. Officially the plan was called the European Recovery Program. Marshall announced the plan in 1947, and it went into effect in 1948. The intent was to provide aid and rebuilding to European economies after the damaging effects of World War II.
In his speech introducing the plan, Secretary Marshall presented the plan as aid for any and all nations, saying : "Our policy is not directed against any country, but against hunger, poverty, desperation and chaos. Any government that is willing to assist in recovery will find full co-operation on the part of the United States. Its purpose should be the revival of a working economy in the world so as to permit the emergence of political and social conditions in which free institutions can exist." <em>[I provided more context for the quote you had shown, to see more of his intent in the remarks.]</em>
The view in the communist-controlled Eastern bloc was that the US was trying to use such a policy to spread its influence and threaten their patterns of government under communism. So the plan ended up building allies for the US in Western Europe, while the Eastern European countries sided with the Soviet Union. So it was an example of Cold War tactics of competition between the US and the USSR, apart from the use of military force.
