Christian Brose was the staff director of the Senate Armed Services Committee, and he was also John McCain's senior policy adviser. He now works as the chief strategy officer of Anduril Industries, and he is the author of "The Kill Chain: Defending America and the Future of High-Tech Warfare," a look at how far behind the United States is growing in possible conflict against its principal national security adversary: China. Benjamin Wittes sat down with Chris to talk through what would happen if China and the United States actually fought a war. How has China modernized its military so quickly without the kind of military spending the United States has engaged in? And what does the United States need to do to stay current?