What was the south’s greatest concern when california applied for statehood?

The main concern would be that California entered as a free state, messing with the balance of slave and free states in the U.S Senate.

The House was free-leaning, as more people lived in the north than the south, but as every state sent only 2 representatives to the U.S Senate, the south was keen on keeping the balance there.

One key element is humour! the man probably represents a politician or worker!