Look at who the owners of breweries and distilleries were pre-Prohibition, and after. Before - small businesses, essentially micro-brewers, spread out across the country. After - Anheuser-Busch and a few others. QED.
Just look at who the world powers were pre-World War, and after.
The idea was to allow Germany and Russia to slug it out, completely exhausting both countries.
See for example the views of Charles Lindbergh (search for Russia) : http://www.pbs.org/wgbh/amex/lindbergh/sfeature/fallen.html
America's strength is why the USD became the reserve currency of the world. Note that the Bretton Woods conference was held in 1944, before the war ended: http://en.wikipedia.org/wiki/Bretton_Woods_system