The Navy is beginning to make the case more openly that the nation needs to get serious about replacing its fleet of Ohio-class ballistic-missile submarines. "We have to have that submarine," Rear Admiral Barry Bruner, the Navy's director of undersea warfare, told the New London Day last week. That's the hometown paper of General Dynamics" Electric Boat, the lone U.S. shipyard building Navy subs. The $90 billion program will refurbish only one of the nuclear triad's three legs (the other two, both operated by the Air Force, deliver their nukes via land-based missiles and bombers, both of which also need replacing). The nonprofit Ploughshares Fund released a study Monday estimating the cost of maintaining, operating and retooling the nuclear triad will cost close to $400 billion over the coming decade (graphic on same for those who disdain too much text). Yet we're getting less bang for the buck, if you will. The Natural Resources Defense Council has noted the declining number of warheads per platform since the Cold War's end: 1991: 7.5 warheads per delivery vehicle (9,300 warheads on 1,239 delivery vehicles) 2001: 5.8 warheads per delivery vehicle (6,196 warheads on 1,064 delivery vehicles) 2009: 2.6 warheads per delivery vehicle (2,200 warheads on 850 delivery vehicles) The military argues that the triad remains necessary to ensure that if an enemy wipes out two legs, the third leg will survive to retaliate (why this doesn't argue for a quadad or a pentad - or, for that matter, a dyad - has never been made clear). The Pentagon's fear of concentrating all of its nuclear eggs in one basket certainly doesn't apply to its ammo production, according to a 2010 article in Army Sustainment, the in-house journal of Army guys who worry about such things: Over 99 percent of all small-arms bullets (5.56-millimeter [mm], 7.62-mm and .50-caliber) consumed by the Army under its Title 10 responsibility to supply and equip its forces are manufactured at the Lake City Army Ammunition Plant...Logisticians will argue that this strategy lacks adequate redundancy and responsiveness... It's clear that nuclear theology has its own sacraments that don't apply to bullets, but 20 years after the end of the Cold War it may be time to ask why. The triad remains a trinity to the U.S. nuclear priesthood. Originally created as a way to outfox the Soviet Union - with a trio of delivery devices, Moscow could never deliver a bolt-out-of-the-blue strike that would destroy all U.S. nuclear weapons. That was the Cold War nuclear theology. But the dogma has changed. Think of it as a kind of atomic Vatican II. Battleland has been asking military officials for years how much the U.S. nuclear arsenal has to shrink before continuing to invest in the triad's subs, missiles and bombers no longer makes sense. "Good question," Air Force Secretary Michael Donley said when we asked him in April. "The more complex the global environment becomes," Donley said, "the more flexibility you want between land, sea, and air-based capabilities." Battleland: So when we get down to three nukes we'll still have a triad? Donley: I wouldn't forecast what levels are the break points here, but I do think it's important to maintain the flexibility and the options for the President going forward. There's no doubt in my mind that the international strategic environment is much more complex than it was when we developed this concept and capability back in the "50s and "60s. So there you have it: the triad was vital in the simple superpower world. It's even more critical today, in the complex, post-Cold War world.