The Cold War pitted east against west, the spectre of nuclear annihilation casting a shadow from the mid 20th century onwards.
Wars were fought by proxy. In Vietnam and Afghanistan, each side armed and backed ideological groups.
There were other fronts too.
The space race represented the battle for technological supremacy, while the Olympic Games offered a rare chance to compete in the physical arena.
Art was another border.
In 1950, the CIA founded the International Organisations Division (IOD) - designed to influence hundreds of different arenas, all with one purpose: to spread America's cultural influence.
At the time, the US was openly hostile to new ideas. McCarthyism was scything through the ranks of American intellectuals. Anything even vaguely counter cultural was viewed with suspicion.
The nation wasn't exactly selling itself as a bastion of free thought and speech.
Abstract expressionism, an entirely new way of thinking about art, was a breath of fresh air. The government pounced.
In contrast to the perceived rigid conformity of Soviet painting, the form encouraged a breaking with tradition - establishing a new way of seeing the canvas.
In a 1995 interview with the Independent newspaper, former IOD officer Donald Jameson explained: "It was recognised that Abstract Expression- ism was the kind of art that made Socialist Realism look even more stylised and more rigid and confined than it was. And that relationship was exploited in some of the exhibitions.
"In a way our understanding was helped because Moscow in those days was very vicious in its denunciation of any kind of non-conformity to its own very rigid patterns.
"And so one could quite adequately and accurately reason that anything they criticised that much and that heavy- handedly was worth support one way or another."
Through another organ, the Congress for Cultural Freedom, the CIA sponsored huge exhibitions of abstract expressionist art that toured around the world.
And the artists involved never had any clue.
This led to artists like Jackson Pollock and Mark Rothko (of Russian descent but who moved to the US aged 10 - what a coup!) becoming household names, growing the global market and giving rise to the situation he have today - where their works change hands for tens of millions.
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