The poppies are the popular issues that keep the public distracted from the real goings on...much like the current media attempts to do....(and the President to a certain degree using that tactic against the press)
The Emerald City represents Washington DC, afloat in greenbacks (transition from the gold standard to paper money) and the Wizard is a generic president.
By the way...Oz is the abbreviation for ounce (of gold)
The tin woodsman represented people turned into machines with no heart (factory workers) by the Wicked Witch of the East, (Industrial revolution) and the Scarecrow was the Midwestern farmer who believed he had no voice in DC (treated as stupid) oppressed by the Wicked Witch of the West...the drought. Dorothy killed her with water.
The flying monkeys were supposed to be the American Indians.
I'm gonna go with this take. It's quite excellent. Witch as drought killed by water is awesome. And so is Emerald City as greenbacks.