New technologies enable Russia and China to destroy U.S. bases and logistics networks—including those on the homeland. For most of its history, the United States has had the luxury of fighting its wars from safe havens. No major international battles have taken place on the continental United States in more than two centuries, and its offshore territory has not suffered a serious attack since Japan bombed Pearl Harbor in World War II. For the past few decades, even U.S. bases on foreign soil have faced few conventional military threats. The unprecedented immunity has enabled a particular American way of war...