The historian in me says that from the not too distant future we’ll look back and see 2017 and the time around it as a turning point in the way we think about navies and warfare. The world is increasingly characterised by peacetime great-power competition. China is aggressively pursuing its interests on its periphery and beyond, Russia is active on its periphery and beyond. They are investing in new capabilities and working in many ways to challenge the world order that’s prevailed for decades. Such changes are already driving the size and composition of the US Navy and other fleets.