PHILADELPHIA — Dave McCormick outlined six aggressive measures Thursday that he thinks the United States should take against China to curb what he described as a danger to American security and economic independence as he tries to out-hawk Sen. Bob Casey in his bid for the U.S. Senate. “Today we face a shadow growing on the Pacific horizon and we cannot be caught by surprise again as we were in 1941,” McCormick said in a speech in Philadelphia on the anniversary of the Japanese attack on Pearl Harbor. His talk marked the biggest showing yet of a new tactic for the Republican candidate, whose 2…