Question

What where Karl Marx main contributions to economics thoughts and policies?

Answer 1

He establish capitalism

Answer 2

Actually, Karl Marx analyzed capitalism and its flaws eventually writing several works advocating an overthrow of the classes. He also co-authored "The Communist Manifesto".

His work would eventually be referred to as Marxism which would promote socialism as the inevitable successor to capitalism. It would also be one of the foundation blocks for the communist theory, Marxism-Leninism, that would form the backbone for communist theory in the Soviet Union and amongst its allies.

Answer 3

None whatsoever. Marx had unoriginal ideas about economics, all of which were either obviously wrong or conventional and already well-understood. His contributions, if you want to call them that, are in the field of politics. That is, he had things to say about politics -- about the means of governing -- which were new and interesting.