Hudson Institute – The US fleet of nuclear-powered attack submarines (SSNs) has long been considered an asymmetric advantage against potential adversaries like the People’s Republic of China (PRC) and Russia, which lacked robust and effective anti-submarine warfare (ASW) capabilities. Relying on this advantage, the US Department of Defense (DoD) has increasingly relied on SSNs to compensate for the impact of improved air defenses on the ability of bombers and strike fighters to execute attacks. However, the unfailing ability of US SSNs to reach their targets is eroding as emerging technologies and weapons proliferation combine in new approaches to ASW that could neutralize America’s undersea advantage.