Talmud Torah or contribution to Am Yisrael (and to the world)?

The Gemarah says that Mordechai went down in stature due to his neglecting his Talmud Torah in order to save the Jewish People. How are we to understand this?

Which is better, contributing to the Jewish People/ the World or learning Torah? What leads to human perfection? What is a tzaddik?

A crucial analysis for our times!