Washington Post heiress Lally Weymouth‘s annual Fourth of July party in Southampton was a balance of DC and New York power players. Revelers included Rudy Giuliani and Sen. Chuck Schumer — who were seated next to the former Newsweek editor-at-large at the dinner — George Pataki, billionaires Wilbur Ross and Leon Black, director Joel Schumacher, and financiers Alan Patricof, Stan Shuman and Jeffrey Leeds, showing off new girlfriend Elizabeth Marshall.Also there was Manhattan DA Cy Vance, who despite the collapse of the DSK case looked “as cool as a cucumber.”