As part of its ongoing strategic “pivot” towards the Pacific, early this year the Defense Department announced it would design a new missile able to quickly cross long distances and penetrate sophisticated air defenses, of the kind rapidly proliferating across Asia. The so-called “conventional prompt strike option” would be submarine-launched, the Pentagon said in its January Defense Budget Priorities and Choices release.

The department placed great emphasis on the new weapon, declaring that “we had to invest in capabilities required to maintain our military’s continued freedom of action.”

But 11 months later, the Pentagon has yet to take meaningful, practical steps towards developing the prompt strike option, casting into doubt the department’s ability to solve the kind of anti-access, area-denial problem posed by, for example, China’s fast-modernizing navy and air force.

“The department is investigating the technologies that would be required for a conventional prompt global strike weapon,” Lt. Col. Melinda Morgan, a spokesman for the Office of the Secretary of Defense, told Breaking Defense. But, she went on, “the department has not made any specific concept decisions at this time.”

The delay reflects political and bureaucratic uncertainty. By contrast, technologies that could contribute to a fast, long-range, sub-launched strike weapon are ready, or very nearly so. And the platforms for launching the weapon — that is, the Navy’s nuclear-powered attack submarines — will soon be compatible with a wide range of possible missile designs.

“The ability of submarines to launch missiles covertly is well documented,” Bob Hamilton, a spokesman for General Dynamics Electric Boat, America’s main submarine-builder, tells Breaking Defense. The sub industry is just waiting for the military to provide a new weapon, Hamilton says.

The result is an impasse. The need for a prompt global strike weapon seems clear. The fleet is ready. Industry is ready. But policymakers have yet to make good on their year-old promise to advance the new missile.

The reasons are clear. Flattening budgets are always an issue. And for all their tactical promise, prompt global strike concepts pose some dicey strategic problems that could continue to stymie their development.

Ballistic Worry

Prompt global strike has its roots in the hunt for Al Qaeda leader Osama Bin Laden more than 12 years ago. Twice in September 2000 the Central Intelligence Agency pinpointed Bin Laden’s precise location near Kandahar in southern Afghanistan, but both times there were no armed military assets — fighter-bombers, missile-equipped drones or naval vessels armed with cruise missiles — close enough to promptly strike before the terrorist chief moved.

The main issue was time. The Air Force’s B-2, B-1 and B-52 heavy bombers boast global range but can require half a day or more to reach a target, even leaving aside the need to carefully coordinate aerial refueling. Likewise, it’s rare that the Navy doesn’t have at least one submarine, destroyer or cruiser carrying Tomahawk cruise missiles within firing range of a major conflict zone. But the Tomahawk is subsonic. If the target is hundreds or thousands of miles from the launching ship, a Tomahawk strike could take hours.

Today armed drone aircraft belonging to the CIA, Air Force and Army are often close enough to strike targets quickly, but these Unmanned Aerial Vehicles are loud, slow-flying, and defenseless — and therefore all but useless against a well-armed foe.

A truly effective prompt global strike weapon needs to be fast — that is, supersonic (at least Mach 1) if not hypersonic (Mach 5 and faster) — plus hard to shoot down. In 2004 Marine Corps Gen. James “Hoss” Cartwright, a vaunted military free-thinker, took charge of U.S. Strategic Command. One of his priorities was to solve the prompt-strike problem.

Starting in 1998 the Navy and Raytheon had worked on a land-attack version of the ubiquitous Standard surface-to-air missile, which would have had an approximately 500-mile range, supersonic speed and enough explosive power to take out a vehicle or a small building. But the Pentagon terminated the land-attack Standard development in 2003, forcing Cartwright to start from scratch with his prompt global strike weapon.

He found a potential solution in the Navy’s Trident ballistic missile, which is launched by the sailing branch’s Ohio-class strategic submarines and has only ever been fitted with a nuclear warhead. Swapping the Trident’s nuclear warhead for high explosives would produce a fast, long-range strike weapon that was almost impossible to shoot down.

“Cartwright pushed a conventional Trident option,” recalled Owen Cote, a professor and naval analyst at the Massachusetts Institute of Technology. The 2006 Quadrennial Defense Review made Cartwright’s ambitions official policy.

Equipping the hypersonic, highly ballistic Trident with a non-nuclear warhead is not technically complicated, but Cartwright and other global strike advocates knew it would be politically controversial. “The conventional Trident option kept running up on reefs having to do with accidental nuclear war,” Cote explains.

There were concerns that Russia might detect the launch of a conventional Trident from an Ohio-class submarines and mistake the missile for the opening shot of a nuclear first strike, because there’s no way to tell from the outside whether there’s a nuke or just high explosive inside the warhead. “Early warning satellites and radars cannot distinguish between the launch of a conventional missile and that of a nuclear one,” Pavel Podvig wrote for the Washington, D.C.-based Center for Strategic and International Studies. Congress rejected most of the proposed $127 million in 2007 funding for the conventional Trident.

To reinforce the case for building the conventional Trident, the Pentagon commissioned the National Academy of Science to study prompt global strike. Albert Carnesale from Harvard University headed the research team. Their 2007-2008 study endorsed the conventional Trident as the best means of striking fleeting terror targets, and also concluded that a non-nuclear, submarine-launched ballistic missile could be useful for a “leading-edge” attack during the initial stages of a shooting war with a major power — China, for instance.

But the Carnesale study admitted that “ambiguity” — that is, nations mistaking a conventional Trident for a nuclear one — was a problem, and it advocated using conventional ballistic missiles only at relatively short ranges of just a few thousand miles, as opposed to the truly global range of nuclear missiles. The constrained range could result in unique trajectories that Washington could advertise in advance as belonging only to non-nuclear attacks.

Congress remained unconvinced. “There was widespread, but not universal, agreement that the Congress should not proceed with the conventional Trident program,” Senators Daniel Inouye (D-HI) and Ted Stevens (R-AK) wrote in response to the Carnesale study. “Critical to the opposition was a belief that the Trident option proposed the most difficult challenges of ambiguity.” For several years Congress continued zeroing out proposed funding for the conventional Trident.

Congress advised the Pentagon to consider other prompt-strike options, namely hypersonic cruise missiles. But subsequent tests of hypersonic vehicles by the Air Force, Army and Navy resulted in more failures than successes. An August test flight by the Air Force’s Mach-6 X-51, the third since 2010 for the Boeing-made missile, ended after just 16 seconds when a control fin failed. The Air Force had been hoping to eventually weaponize the X-51.

The failures have been predictable. The high temperatures encountered during Mach 5 or faster flight exceed the tolerances of today’s designs and materials, wreaking havoc on airframes and control systems. More high-speed tests are planned, but Cote for one is skeptical. Hypersonics, he says, “will never happen.”

Strike Options

Cartwright eventually rose to the position of vice chairman of the Joint Chiefs of Staff. Prompt global strike “stayed alive because of that,” Cote says. And when Cartwright retired late last year, the concept’s proponents retained enough clout to give it another big push. The opportunity came with the advent of the AirSea Battle doctrine for fighting a high-tech air and naval war, as well as with the broader Pacific pivot.

Prompt global strike had originally been intended primarily as a counter-terrorism weapon, but it had always had a potential use in conventional war. With China’s rise as a global power, that kind of conflict was looking more realistic, though still unlikely. Today prompt global strike enjoys continuing support from Pentagon China hawks, whom Cote calls “panda-haters.”

Bin Laden’s death and the decline of Al Qaeda only accelerated the shift in mission for global strike, from taking out terrorists to destroying high-tech targets — air defenses, for example — during major war. “This capability may bolster U.S. efforts to deter and defeat adversaries by allowing the United States to attack high-value targets or ‘fleeting targets’ at the start of or during a conflict,” the Congressional Research Service posited in a July report on prompt global strike.

A smaller non-nuclear ballistic missile than the Trident, optimized for an intermediate range of just a couple thousand miles — a twist on Carnesale’s advice — is the best choice for a near-term prompt strike weapon, according to CRS. “It could attack targets quickly, both at the start of a conflict if the submarines were within range, and during the conflict if new targets emerged. Its speed and angle of attack might also make it capable of attacking some types of hardened or buried targets. It might also be able to penetrate an adversary’s defenses without putting aircraft or crews at risk.”

What’s more, the Navy’s new Virginia-class submarines are already being fitted with launch tubes that could accommodate a smaller ballistic missile. “We would need more information about the specifications of this weapon to answer this question definitively, but the next Virginia-class ship to be launched will have an innovation that will make it much easier to accommodate dramatically different payloads,” Electric Boat spokesman Hamilton told Breaking Defense. “North Dakota, SSN 784, and follow-on ships will have two large-diameter bow tubes, replacing a dozen 21-inch vertical launch tubes.”

Moreover, Virginia-class vessels planned for production starting in the 2020s are likely to feature the so-called “Virginia Payload Module,” which would add four more of the large-diameter tubes and triple the subs’ payload capacity, according to Hamilton. Not coincidentally, that module was endorsed in the same Pentagon budget document that announced the revived prompt strike missile.

But to field such a weapon the Pentagon would still have to finally overcome the ambiguity problem and convince a skeptical Congress — two very big ifs. The Navy is optimistic. An intermediate-range weapon would probably have just two stages, compared to the Trident’s three. For that reason there would be “immediate observable differences at launch” between the new missile and a Trident, Navy officials said.

CRS still has doubts. “It would not eliminate all possibilities of misunderstanding,” the research service said of the proposed missile.

Funding is also a challenge. Congress gave the Defense Department nearly $175 million for global-strike development in 2012, but just under half of that was for (ultimately failed) hypersonics efforts. The Navy reportedly got just $10 million to study a submarine-launched weapon; another $90 million was for warhead development.

Present plans foresee $110 million in total global strike development funding in 2013, $140 million in 2014, $250 million the year after that, rising to nearly $280 million in 2016 and $340 million the next year, for a total of more than a billion dollars over five years. But those projections did not take into account the possible effects of budget sequestration, which could begin early next year unless Congress and the Obama administration can agree on a deficit reduction deal — which would likely cut defense anyway.

Nor do the plans figure the cost of buying weapons. “The current conventional prompt global strike effort is an R&D activity, not an acquisition program, therefore the department does not have a total cost estimate to field a weapon system,” OSD spokesman Morgan said.

Even so, a formal acquisition of the revitalized strike weapon is scheduled to begin in 2013 or 2014, according to Pentagon documents, but “timing will be driven by the outcome of flight events and DoD budgets.” On that point, it’s worth noting that there have been no successful, unclassified flight events in support of prompt global strike development this year.

The pieces exist for a weapon that would finally fulfill Cartwright’s nearly decade-old vision of fast-reacting, unstoppable, non-nuclear strike. But the Pentagon has yet to put the pieces together.