The U.S. Department of Defense is scrutinizing all three legs of the nation’s aging nuclear triad as part of its nuclear posture review, Defense Secretary Jim Mattis said June 14.

“We’re looking at each leg of the triad and we’re looking at each weapon inside each leg,” Mattis testified before the Senate Appropriations Committee’s defense panel. “What I’m looking for is a deterrent that will be most compelling to make certain that these weapons are never used.”

Defense Secretary Jim Mattis testifies before the Senate Armed Services Committee June 13. (DoD photo)
Defense Secretary Jim Mattis testifies before the Senate Armed Services Committee June 13. (DoD photo)

Mattis’ comments came in response to Sen. Dianne Feinstein (D-Calif.), who urged DoD to determine which nuclear modernization efforts are truly needed for deterrence and which are not.

“The nuclear posture review, I hope, will prioritize nuclear weapons investments,” she said.

The department currently plans to replace aging Navy ballistic missile submarines, Air Force bomber aircraft, Air Force land-based intercontinental ballistic missiles and the weapons the new platforms will carry. But it will struggle to afford all of those items, which are expected to cost hundreds of billions of dollars.

Feinstein specifically urged Mattis to take a “new look” at the Long Range Standoff Weapon (LRSO), a planned replacement for the Air Force’s Air Launched Cruise Missile (ALCM). She cited not only its cost but its potentially “destabilizing” attributes, which she said she could not discuss in a public session.

“It’s got features that concern me greatly,” she told Mattis. “I do not see it as an effective deterrent weapon. I see it as Russia taking action to counter it.”

Mattis said he is weighing such concerns about the LRSO against the need to ensure that Air Force bombers can deliver nuclear weapons from standoff ranges.

“I’ve got to do more study,” he told Feinstein.

DoD announced in April that it had formally begun the nuclear posture review and would send a report to President Donald Trump by year’s end.

Also at the hearing, Mattis testified that he expects DoD’s ballistic missile defense review, which is running concurrent to the nuclear review, will make the case for “more capability” in missile defense.

“I’ve got to go through some work first before I bring you simply a large bill,” Mattis said in response to a question from Sen. Lisa Murkowski (R-Alaska), whose state hosts long-range, ground-based interceptors. “I’m very confident this threat is not going to get less in the future.”

Mattis called the Terminal High Altitude Area Defense System (THAAD) “critical” to protecting South Korea against North Korean ballistic missiles and expressed confidence that the United States ultimately will receive approval to finish deploying a THAAD battery in South Korea.

While two interceptor launchers have been fielded, South Korea’s new government is insisting that an environmental impact statement be completed before four more launchers are deployed.

“I think we’re going to find our way forward,” Mattis said in response to a question from Sen. Susan Collins (R-Maine).