Why didn't Jorge Luis Borges get the nobel prize?

I have long wondered this.

It seems he refused to write Propaganda for the USA during WW2, opposed (or did not support) 1930's social reforms, and made his craving for the prize too clear.

Apparently he was considered by the committee in 1950.

He was very (too?) popular in America, and did win four Pulitzers - possibly a continuing dispute between the two committees (Nobel and Pulitzer). These committees are well known for political or ideological agendas.

I hope somebody out there can narrow this down a bit, or add to it.