Apparently during the Cold War the CIA purposefully spread modern art as a way to demonstrate that America was more liberal than the Soviet Union:
In 1947 the State Department organised and paid for a touring international exhibition entitled "Advancing American Art", with the aim of rebutting Soviet suggestions that America was a cultural desert. But the show caused outrage at home, prompting Truman to make his Hottentot remark and one bitter congressman to declare: "I am just a dumb American who pays taxes for this kind of trash." The tour had to be cancelled. 
The US government now faced a dilemma. This philistinism, combined with Joseph McCarthy's hysterical denunciations of all that was avant-garde or unorthodox, was deeply embarrassing. It discredited the idea that America was a sophisticated, culturally rich democracy. It also prevented the US government from consolidating the shift in cultural supremacy from Paris to New York since the 1930s. To resolve this dilemma, the CIA was brought in.
It is interesting to think of this in the context establishing a prior probability on the likelihood of conspiracies- on the one hand, we see a clear example of a governmental agency seeking to influence aspects of life way outside of their defined mission. On the other hand, this demonstrates a limit on the size that conspiracies can take. It is hard to do whatever it takes to propagate a message (in this case, "America is the best"), when tactics for doing so conflict with other values. The more entities that are cooperating, the fewer things they can agree on.