MINOT AIR FORCE BASE, N.D. — Calling the nuclear mission "the bedrock of our security, and the highest priority mission of the Department of Defense," Secretary of Defense Ash Carter today offered a full-throated defense of the need to modernize all three legs of the nuclear triad.

Carter's comments came during a visit to Minot Air Force Base in North Dakota, home to both B-52s and Minuteman III intercontinental ballistic missiles. Defense News is travelling with Carter this week.

Under the fiscal year 2017 budget request, Carter said, the department pledged $19 billion to the nuclear enterprise, part of $108 billion planned over the next five years. The department has also spent around $10 billion over the last two years, the secretary said in prepared comments.

The "nuclear triad" references the three arms of the US strategic posture — land-based ICBMs, airborne weapons carried by bombers, and submarine-launched atomic missiles. All of those programs are entering an age where they need to be modernized.

Pentagon estimates have pegged the cost of modernizing the triad and all its accompanying requirements at the range of $350 to $450 billion over the next 10 years, with a large chunk of costs hitting in the mid-2020s, just as competing major modernization projects for both the Air Force and Navy come due.

Critics of both America’s nuclear strategy and Pentagon spending have attempted to find ways to change the modernization plan, perhaps by cancelling one leg of the triad entirely. But Carter made it clear in his speech that he feels such plans would put America at risk at a time when Russia, China and North Korea, among others, are looking to modernize their arsenals.

"If we don’t replace these systems, quite simply they will age even more, and become unsafe, unreliable, and ineffective. The fact is, most of our nuclear weapon delivery systems have already been extended decades beyond their original expected service lives," Carter said. "So it’s not a choice between replacing these platforms or keeping them … it’s really a choice between replacing them or losing them. That would mean losing confidence in our ability to deter, which we can’t afford in today’s volatile security environment."

He also hit at critics of the nuclear program — which include former Secretary of Defense William Perry, widely seen as a mentor for Carter — who argue that investing further into nuclear weapons will increase the risk of atomic catastrophe in the future.

"None of these investments is intended to change the nature of deterrence or how it works; after all, no one can. And not only are they not intended to stimulate competition from anyone else; we know they aren’t having that effect, because the evidence is to the contrary," Carter said. "We didn’t build anything new for the last 25 years, but others did — including Russia, North Korea, China, India, Pakistan, and, for a period of time, Iran — while our allies around the world — in Asia, the Middle East, and NATO — did not."

Carter expressly called out Russia for its "recent nuclear saber-rattling" that "raises serious questions" about Moscow’s commitment to the global post-Cold War nuclear posture. In contrast, the secretary said China "conducts itself professionally in the nuclear arena, despite growing its arsenal in both quantity and quality."

While the efforts to modernize the ICBM, bomber and submarine fleets garner major attention, there is a second tier of vital nuclear programs – including the command-and-control structure, the B61-12 warhead upgrade, and the Long Range Standoff (LRSO) nuclear cruise missile – that are also part of the modernization effort.

Notably, Minot is home to several hundred Air Launched Cruise Missiles (ALCMs), which provide the US stand-off, plane-launched nuclear strike capability and which would be replaced with the LRSO. Those weapons are increasing in age, with one maintainer telling reporters here that the Pentagon is exploring the use of 3-D printing to help compensate for out-of-production parts vital to the weapon.

The LRSO has become a popular target for Congress and the nonproliferation community, with the argument being made that the capability is duplicative to conventional stand-off weapons.

Speaking at least week’s Air Force Association conference outside Washington, Gen. Robin Rand, head of Air Force Global Strike Command, defended the need for the LRSO program to continue.

"The deterrent value of it; the options that it gives the president," Rand responded when asked why the weapon was needed. "The ability not to penetrate enemy airspace, not to fly directly to the target. I don’t believe we should put 100 percent of our eggs all in one basket and solely rely on stealth, so this gives you a long-range strike capability."

Rand then presented a broader justification for the triad as a whole, one in line with Carter’s comments Monday.

"We say the ICBM land-based missile gives us incredible responsiveness. We are on 24/7 alert. The air leg gives us tremendous flexibility. You can generate them, you can show that you’re generating, they can take off, and you can recall. You can’t recall a sea or a land based missile. Once it comes out of the hole you ain’t getting that bad boy back," Rand said. "The sea-based gives you tremendous survivability. Those are options that I think the president has found, every president since President Eisenhower, has found those to be compelling reasons to keep the triad."

Aaron Mehta was deputy editor and senior Pentagon correspondent for Defense News, covering policy, strategy and acquisition at the highest levels of the Defense Department and its international partners.

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