Gettysburg became a postbellum focus of the "Lost Cause", a movement by writers such as Edward A. Pollard and Jubal Early to explain the reasons for the Confederate defeat in the war. A fundamental premise of their argument was that the South was doomed because of the overwhelming advantage in manpower and industrial might possessed by the North. They also contend that Robert E. Lee, who up until this time had been almost invincible, was betrayed by the failures of some of his key subordinates at Gettysburg: Ewell, for failing to seize Cemetery Hill on July 1; Stuart, for depriving the army of cavalry intelligence for a key part of the campaign; and especially Longstreet, for failing to attack on July 2 as early and as forcefully as Lee had originally intended. In this view, Gettysburg was seen as a great lost opportunity, in which a decisive victory by Lee could have meant the end of the war in the Confederacy's favor.