On Tuesday, Mastro won a temporary restraining order barring plaintiffs lawyers from acting to enforce any judgment an Ecuadorian court issues against Chevron in the long-running Lago Agrio litigation. But that's just the latest of the remarkable victories he and Gibson Dunn have won in the New York wing of this sprawling case.

As chief counsel for the U.S. Senate Banking Committee in the mid-1990s, Giuffra helped draft the Private Securities Litigation Reform Act and hobble stock-drop suits. Since the financial crisis the PSLRA has gotten a vigorous workout; last Friday it gave Giuffra the ammunition he needed to knock out what remained of a class action against UBS over more than $100 billion in losses.