As the new executive committee chairman of Steptoe & Johnson LLP, Philip West aims to sharpen the firm’s image and build key practice areas — but he’s on the fence about whether a merger makes sense.

The head of the firm’s tax group and a former top international tax lawyer at the U.S. Treasury Department, West took the helm of the 411-lawyer firm on Jan. 1 from Roger Warin, who led Steptoe for the past decade.