After that political asylum became a big thing because of equally obvious reasons (Communism).
1. Race
2. Religion
3. Nationality
4. Political opinion,
5. Membership in a particular social group.
This is where US law gets complicated. There's something called the Chevron Doctrine or Chevron Defense.
en.wikipedia.org/wiki/Chevron_U….
One of those laws is the laws on asylum and how social groups are defined. Obama defined them one way, now Trump is defining them another.