The Wizard of Oz has always been described as a basic allusion to Populism in the 1800's. Through its detailed use of symbols in objects to the characters in the movie, it is a classic example of the Populist Movement in America.
The Wicked Witch of the East was portrayed in the movie as a tyrannizing and evil woman who wanted control over everything within the Land of Oz, just as she controlled the munchkins as her slaves. This is representative of the Eastern industrialists and bankers who sought out to have control over all the people. (http://www.halcyon.com/piglet/Populism.htm)
The naïve scarecrow in The Wizard of Oz was used to portray the intelligent and wise Western farmers during this time period. When all he ever wanted was a brain but it turns that he was one of the wisest people, he was just too naïve to use it. (http://www.halcyon.com/piglet/Populism.htm)
The Tin Woodman in the Wizard of Oz was a man who all he wanted was a heart. This was a direct reference to the dehumanizing factors that the industrial workers had to face during this time period. Their work and stress of staying alive with the economy and conditions changed them in ways that most people could not bear today. (http://www.halcyon.com/piglet/Populism.htm)
Of course the lovely, magical, and beautiful Emerald City was the allusion to Washington D.C. during this time period. A place most people dreamed of going to in order to let their voices be heard from the great Oz himself, or otherwise known as the President. (http://www.halcyon.com/piglet/Populism.htm)