How Did The Purchase of The Louisiana Territory help the United States Avoid War With European Powers ?

One big change in the global economy after World War II, as compared to before the war, was a pattern of steady growth.  From 1950 to 1973, the average annual GDP growth of market economies in the developed world averaged around 5% and remained rather steady.  This was a strong improvement over the convulsions of the Depression that had happened prior to the Second World War.  

Also over the decades after the World Wars, the global economy became more interconnected than ever before as well.  Granted, during the Cold War years there was a wall (or shall we say an iron curtain) between the connected economies of the democratic countries and the connected economies of the Soviet bloc of nations.  But eventually the communist system would collapse, and the increasing globalization of economies would continue and accelerate into the 21st century.  

As nations like the United States have shifted more and more toward service economies rather than manufacturing economies, developing nations of the world have advanced strongly in the global economy through industrialization and growth of industrial production.  So now there are new economic powerhouses in the world, such as India and China, which played a much smaller role in the global economy a century ago.