Conversation so far:
What is the Principles of justice?
The first of these is the Liberty Principle.
What is the Liberty Principle?
establishes equal basic liberties for all citizens.
What is another principle?
a two-part second principle comprising Fair Equality of Opportunity and the famous (and controversial) difference principle.
Why is the difference principle controversial?
CANNOTANSWER.

Question: What is the Fair Equality of Opportunity principle?
Self-contained rewrite: What is the Fair Equality of Opportunity principle?