This Week at War: Bombs vs. Shovels

My Foreign Policy column discusses the arms race between big bombs and deep tunnels. I also discuss the new Marine Corps base in Australia and moral hazard.

Hard targets require big bombs. Big bombs need big airplanes

This week, Bloomberg News reported that in September the U.S. Air Force began receiving the first deliveries of a new 30,000-pound bunker-busting bomb. Called the Massive Ordnance Penetrator (MOP), the new bomb is six times heavier than the 5,000-pounder that was previously the Air Force's most-powerful non-nuclear munition. According to Bloomberg, the Air Force's intercontinental B-2 stealth bomber has been equipped to deliver the MOP.

Development of the MOP began in 2004 in response to a request from the Pentagon's Defense Threat Reduction Agency (DTRA), which develops programs for countering enemy weapons of mass destruction. Potential adversaries have increasingly turned to underground bunkers and tunnels to protect their most valuable assets. Iran's underground uranium enrichment facilities at Natanz and Qom are quintessential "hardened and deeply-buried targets," a focus of DTRA's attention. North Korea has decades of experience digging tunnels and bunkers for its weapons and military storage facilities. China may have thousands of miles of tunnels set aside for military purposes, the exact nature of which remain a mystery.

In July 2009, the U.S. Central and Pacific commands made an urgent request to accelerate the MOP's development, and the bomb was delivered to the Air Force three years earlier than planned. This request was presumably in response to the discovery of new hardened targets these commanders might be asked to strike and which were too deep for the 5,000-pound bomb to defeat.

There is an arms race underway between the diggers and the bombers. Iran's vast Natanz uranium enrichment plant was built underground to protect it against an air attack. The U.S. Air Force's 5,000-pound bunker-busting bomb may be enough to defeat Natanz's reinforced ceilings. Iran then searched for another site for uranium enrichment and found one in the tunnel system near Qom, which may be under almost 300 feet of rock. MOP's accelerated development may have been in response to the discovery of the Qom facility. The Air Force claims that MOP penetrates 200 feet into the earth before exploding. Whether that would be enough to defeat the Qom facility is unclear. In any case, research on even more powerful conventional earth-penetrating weapons goes on, as U.S. policymakers anticipate that the diggers will keep going ever deeper.

What remains to be seen is whether the Pentagon will find money to maintain this deep-attack capability well into the future. The B-2 (of which the Air Force has just 20) is the only airplane that can deliver the MOP against defended targets; the Pentagon's other stealthy aircraft, such as the F-22 and F-35, are too small to carry the 30,000-pound bomb. Nor do these fighters have the intercontinental range of the B-2. The United States is thus likely the only country that can attack (with a conventional munition) very deep bunkers that are also protected with sophisticated air defense systems.

A top Air Force priority is its next-generation bomber, which would preserve its ability to attack deep bunkers after the B-2 is eventually retired. In an era of defense budget austerity, many analysts have criticized the new bomber program as a niche capability that the Pentagon can't afford.

Military commanders don't like leaving adversaries with untouchable sanctuaries, be they insurgent base camps in Waziristan or tunnels in Iran and North Korea. Strategy in an age of austerity means choosing which risks one is willing to live with. Sustaining a capability to attack the underground world will not be cheap. The alternative is ceding these sanctuaries to an adversary. Pentagon strategists will have to decide whether they are willing to live with that risk.

Will the U.S. base in Australia encourage free-riding?

U.S. President Barack Obama declared in a speech to the Australian parliament on Thursday that the "United States is a Pacific power, and we are here to stay." He reassured his audience that "reductions in U.S. defense spending will not -- I repeat, will not -- come at the expense of the Asia-Pacific." While policymakers in the region wait on that promise, Obama and Prime Minister Julia Gillard announced the permanent basing of up to 2,500 U.S. Marines near Darwin on Australia's north coast. Although a seemingly symbolic move, both the United States and Australia will get some valuable indirect benefits from this agreement.

The U.S. and Australian governments revealed their intention to deepen their military relationship in September. At that time, the discussion centered on greater U.S. access to Australian facilities, not permanent basing of forces. Since then, U.S. officials may have concluded that a more affirmative basing agreement was needed in order to back up Obama's renewed security commitment to the region. But the move starts with just 200 Marines and is no closer to the South China Sea than existing U.S. bases in Guam and Japan. So why bother?

Although initially tiny, relative to U.S. military power in the region, the new U.S. base near Darwin will likely grow to provide important benefits. Over time, the U.S. and Australian funding could expand to fund port and airbase facilities in the area, making the Darwin base a logistics hub supporting larger naval and air operations in the region. The new hub will diversify regional basing options for U.S. commanders, reducing operational risk during crises. The Marine Corps and other U.S. services will gain access to additional training ranges which will improve their readiness. The future hub could develop into a regular location for joint training with other partners from the region, deepening U.S. security relationships. Finally, the Marine Corps commitment to Australia will give its commanders a leadership role in the region, an important asset as the Corps defends its turf back in Washington.

For little cost and risk, Australia gets a boost to the security guarantee provided by its alliance with the United States. Australia's military forces will enjoy the benefits of working with a partner on the leading edge of military doctrine and tactical techniques. In many cases, U.S. and Australian forces will operate similar equipment; a persistent training relationship will deepen interoperability between these forces and improve Australia's military readiness.

In 2009, the Australian defense ministry issued a white paper discussing the country's long-term security interests and challenges. The paper cautiously expressed doubts about whether the United States would be able to fulfill its security guarantee over the long term. As a result, the paper proposed a substantial buildup in Australia's military power, with a focus on pricey naval and air systems, such as a new and expanded submarine force and a large fleet of F-35 Joint Strike Fighters.

Whether Australia will be able to afford this military investment over the long haul is an open question. The now-expanded military alliance with the United States may give it the option to defer having to answer this question. Should Australia decide to proceed with the white paper's proposed buildup, it may now have the option of stretching out its implementation, and spreading out the expense.

This is not the response U.S. policymakers want to see from allies in the region. The Obama administration does not want its renewed commitment to the region to induce complacency among those receiving the U.S. security guarantee. Regrettably, no one has yet figured out an answer to the problems caused by moral hazard -- insurance policies inevitably subsidize both free-riding and risky behavior. Obama has sought to reassure U.S. partners in the region. But he also wants them to step up their own defense efforts. The perennial trick for any American president is how to do both.