WASHINGTON — President-elect Donald Trump's choice for secretary of defense believes the US needs to maintain its intercontinental ballistic missile (ICBM) program, but showed a willingness to consider whether developing a new nuclear cruise missile is the right path forward.

Retired Gen. Jim Mattis made his comments as part of his confirmation hearing in front of the Senate Armed Services Committee, where he was asked whether he would continue to support the nuclear triad modernization strategy pursued by the Obama administration.

"I consider the deterrent to be critical," Mattis said during his testimony, "because we don't ever want those weapons used. So either the deterrent is safe and secure, it is compelling, or we actually open the door for something worse, whether it be a technical accident or political accident. So to me it's an absolute priority."

In written testimony, Mattis made his views clear that "we must continue with current nuclear modernization plans for all three legs of the Triad, and for associated command and control systems," but he offered more specific thoughts when asked by senators about the individual programs, showing enthusiasm for the ICBM leg of the triad, describing it as the most cost-imposing strategic asset for potential enemies.

"It’s clear they are so buried out in the central US that any enemy that wants to take us on is going to have to commit two, three, four weapons to make sure they take each one out," Mattis said. "In other words, the ICBM force provides a cost-imposing strategy on an adversary. What we’re trying to do is set such a stance with our triad that these weapons must never be used."

He also offered support for the recapitalization of the nuclear submarine force and the development of the B-21 bomber, although Mattis emphasized the "manned" aspect of that system, which may be a hint that he would back abandoning the idea of making the B-21 unmanned for conventional missions.

His most measured comments came when discussing the Long-Range Standoff Weapon (LRSO), the new nuclear cruise missile design, and the part of the nuclear modernization that the non-proliferation community has targeted as unnecessary — although even there, he showed support for the development of the weapon.

"I need to look at that one," Mattis said in response to a question about LRSO. "My going in position is that it makes sense, but I have to look at it in terms of its deterrence capability."

The retired general also backed putting nuclear-capable F-35s into Europe in the future, noting in written testimony: "NATO's nuclear deterrence posture relies in part on U.S. nuclear weapons forward-deployed in Europe and on capabilities and infrastructure provided by NATO allies. These capabilities include dual-capable aircraft that contribute to current burden-sharing arrangements within NATO. In general, we must take care to maintain this particular capability, and to modernize it appropriately and in a timely fashion."