SUB BASE NEW LONDON, Connecticut — In the wake of the Cold War, as the Soviets’ once-mighty submarine fleet rusted away, the U.S. Navy let its ability to hunt enemy subs slide. The sea service is remedying that now, adding new maritime patrol aircraft and ship-towed sonars (and experimental robot ships) to hunt a new generation of better, quieter foreign subs.

But there’s one part of the Navy that says it doesn’t need to get back up to speed on anti-submarine warfare: the sub force itself.

“We have always been in that job,” said Cmdr. Dan Reiss, who commands USS New Mexico, a Virginia-class attack sub. “I’ve been in for 17 years, and the focus has always been on anti-submarine warfare.”

He vigorously rejected suggestions that other missions had diverted the sub force from ASW, though he acknowledged that the Navy as a whole faces challenges.

“Anti-submarine warfare isn’t just about subs” because other naval forces are also brought to bear, including maritime patrol aircraft and surface warships, Reiss said. “Some of those areas have become challenged, but as for submarines, we’ve always been focused on it.”

Still, improvements in the submarine fleets of Russia, China, and other navies mean the U.S. needs to hustle to stay ahead, Defense Secretary Ash Carter said a bit later, addressing sailors gathered on a pier next to the moored New Mexico.