It's very clear that there are greater threats to these ships since, arguably, World War II. There are new technologies that can now reach them and make them harder to defend, such as anti-ship missiles, combined with space based tracking. The bigger issue, though, is who are gaining those capabilities. With what's going on with China and Russia, we are returning to geopolitical state-by-state competition. The Navy has not had to fight a peer for control of the sea since the Battle of Midway 75 years ago.