Conversation so far:
What were Shaw's first political activities?
He began attending meetings of the Social Democratic Federation (SDF).
Was he an active member?
CANNOTANSWER.
Is there any additional information about his time with the SDF?
Shaw doubted the ability of the SDF to harness the working classes into an effective radical movement and did not join it.

Question: What did he get involved with next?
Self-contained rewrite: What did George Bernard Shaw get involved with after the SDF?