On March 15, a shooter entered two Mosques in Christchurch, New Zealand. He killed fifty and injured 50 more. He left behind a bizarre and meme-laden manifesto. In February, authorities arrested a Coast Guard lieutenant who had been stockpiling weapons in anticipation of kicking off a race war. When it comes to terrorism, America’s problems are overwhelmingly white and nationalist. In terms or raw numbers, it’s not even close.