"For decades in art circles it was either a rumour or a joke, but now it is confirmed as a fact. The Central Intelligence Agency used American modern art - including the works of such artists as Jackson Pollock, Robert Motherwell, Willem de Kooning and Mark Rothko - as a weapon in the Cold War. In the manner of a Renaissance prince - except that it acted secretly - the CIA fostered and promoted American Abstract Expressionist painting around the world for more than 20 years.
Why did the CIA support them? Because in the propaganda war with the Soviet Union, this new artistic movement could be held up as proof of the creativity, the intellectual freedom, and the cultural power of the US. Russian art, strapped into the communist ideological straitjacket, could not compete.
The existence of this policy, rumoured and disputed for many years, has now been confirmed for the first time by former CIA officials. Unknown to the artists, the new American art was secretly promoted under a policy known as the "long leash""... source
Let's not forget that Hollywood was a propaganda weapon too, intended, and quite successfully, to spread American values abroad.