Dylan Matthews makes a pithy argument:
While subsidies have stabilized in the past few years around $100 billion a year -- a huge number, given that agriculture (not including things like cotton and tobacco) only accounted for $136 billion of GDP in 2009 -- the composition has changed, with general support and consumer subsidies gaining ground and producer subsidies falling. This level of spending, as many have pointed out, artificially lowers the price of U.S. agricultural goods, driving up U.S. exports while undermining (PDF) developing countries' attempts to export food products, which is one of the only industries many of them have.
And yet this is also one of those programs - like the war in Afghanistan or Medicare - that simply cannot and will not be ended, or even cut to within affordable levels.The US is a country crying out for an intervention. And one day, the global markets might finally deliver one.