We have good a priori reasons to doubt that perceptions of intentions could play a decisive role in a great power’s calculations of its theat environment. John Mearsheimer points out that 
unlike military capabilities, which we can see and count, intentions cannot be empirically verified. Intentions are in the minds of decision makers and they are especially difficult to discern.
Moreover, “even if one could determine” the intentions of present leadership of a rival power, “there is no way to know what they will be in the future.” Furthermore, signaling benign intentions by building defensive capabilities doesn’t really work because “capabilities that states develop to defend themselves often have significant offensive potential.”
It is hard to disagree with these claims. When countries launch armament programs they invariably proclaim defensive intentions. The stated goal is always deterrence. The purpose of ongoing Japanese rearmament is to deter China. China’s military buildup is for the defense of Chinese interests against US power. US’ reallocation of military assets to Asia is to deter Chinese aggression. The expansion of states’ war-making capabilities is an expression of their search for security in a dangerous world. But is it true that there is no way to distinguish between defensive and offensive armaments? We’ll come back to this question.
We have stated previously that strategic nuclear weapons are purely defensive, at least against other nuclear-armed states that possess a second-strike capability. On the other hand, missile defense systems undermine the reliability of the enemy’s capability to retaliate and are, therefore, essentially first-strike weapons. More generally, and somewhat counter-intuitively, firepower is largely defensive while mobility is largely offensive. For it is sustained firepower that makes sheltered positions impregnable to assault, while mobile armor, in conjunction with flying artillery, potentially enables an army to effect a rapid strategic penetration against the enemy. That is, it opens up the possibility of conducting a blitzkrieg.
In his PhD dissertation, John J. Mearsheimer showed how the modern battlefield emerged in 1940 with the German deployment of this war strategy; arguing that conventional deterrence is likely to hold if the attacker is incapable of carrying out a blitzkrieg, and unlikely otherwise. Soon after the publication of his thesis, the modern battlefield was transformed by the rise of precision guided munitions (PGMs). These weapons, and even more importantly, developments in information, surveillance, and reconnaissance (ISR) capabilities made hitherto battlefield-dominating industrial era weaponry – tanks and flying artillery – sitting ducks. To put it bluntly, a fight between an advanced weapons state (that is, a state with the full range of PGM-ISR capabilities) and an industrial-era power has become a turkey shoot.
Since the United States is the only state with the full spectrum of advanced weapons capability, one would not be far off the mark to see unipolarity as more or less an artifact of the military-technological gap between the United States and other strong states. Right now, Germany and Japan are the only other states in the international system with the economic, financial, and technological wherewithal to develop an independent advanced weapons capability. At some point in the future, other states (China certainly, and maybe India and Russia) will also acquire these capabilities.
It seems clear that a military confrontation between two advanced weapons states is defense-dominant. This doesn’t just mean that defense is easier than offence – that has always been the case. It means that conventional deterrence is significantly enhanced by PGM-based military technology. It will prove spectacularly difficult to mount a military attack of a territory occupied by a power that can take out any and all military assets of the enemy within hundreds of miles.
By the time another state acquires these capabilities, the range and sophistication of PGM-centric military technology is likely to be considerably more enhanced than is the case today. Even so, the range of cruise missiles that can be cheaply produced in large quantities is unlikely to be much larger than what it is today – around a thousand miles. In a region where two great powers confront each other, the military balance will acquire the characteristics of the balance of terror. Warfare will be much more lethal and survival rates for military forces will be very low; even short campaigns will be as costly as a long-drawn wars of attrition. This is very good news for deterrence between powerful neighbors, who will dare not attack for fear losing most of their military assets in a day’s worth of fighting. If deterrence fails and two neighboring advanced weapons states go to war, it is likely to be brief but extraordinarily costly. After an initial exchange of fire that more or less destroys all military assets of both combatants close the enemy’s lines, they will be separated by a thousand miles that they dare not enter. The thousand-yard ‘zone of fire’ predicted by Bloch in 1902, will be replaced by a thousand mile belt that both sides will stay clear off, for any military asset in this region will be immediately exposed to annihilation.
In this sense, the prospects of conventional deterrence are good. The homeland of an advanced weapons state will enjoy a great deal of security. The same cannot be said of the prospects for extended deterrence. A world power with overseas commitments faces a hierarchy of security interests. The most important objective is always the defense of the homeland. The security of overseas possessions and strategic sea-lanes of communication is secondary to this primary objective of any world power. This is especially so for protectorates that serve little strategic purpose. For instance, the United States will fight tooth and nail for Singapore (due to its geostrategic location), Japan (since it is a great power that can prevent China from becoming a regional hegemon) and the Persian Gulf (crucial to US’ veto over its rivals’ access to energy). The same cannot be said of Taiwan, Korea, the Philippines, and even Guam. To be sure, this second set is crucial to American presence in the Asia-Pacific region. However, American military assets in Taiwan and the Korean peninsula will be especially exposed to long-range cruise missiles launched from Chinese territory where the Chinese control the airspace. Since China’s security interests in these two places is considerably greater than their strategic value to the United States, the American presence here will become untenable as soon as China acquires a large enough arsenal of long-range cruise missiles and the full range of ISR capabilities.
The US will no longer be able to rely on military assets in the region to secure extended deterrence. Rather, it would have to use the threat of escalation to deter China in its ‘near abroad.’ James Dobbins states,
With the passage of time and the improvement of Chinese capabilities, the United States will find itself forced to shift from deterrence by denial, based on direct defense of its interests and allies in the Western Pacific, to deterrence by punishment, based on the threat of escalation, using longer range weapons and more survivable platforms. Although the United States will enjoy escalation dominance for some time, assuming it is prepared to conduct conventional strikes on the Chinese mainland, China will develop escalation options of its own, including anti-satellite and offensive cyber-warfare capabilities, thus increasing US risks in pursuing escalation. Improvements in China’s strategic nuclear forces, and the limited stakes in the most plausible scenarios for Sino-American conflict, will reduce the credibility of any US threat to use nuclear weapons.
In other words, it is highly unlikely that the United States will continue to enjoy escalation dominance against China. As China achieves military parity with the United States, the advantage will inexorably shift to China. It is the US itself that will be deterred from activating its military assets to achieve its foreign policy objectives in the region.
The American presence in Northeast Asia is clearly unsustainable in the long run. The US will be forced to withdraw its military assets beyond the First Island Chain. This is not as big a deal as it sounds. The United States will continue to be the dominant state in the international order and the only world power. That is, unless China defeats the United States in a hegemonic war. Does China intend to challenge the US on the world stage?
Back to intentions
Is there no way to infer offensive intentions from a rising power’s armament program? Surely, it is impossible for a state to plan major war without developing specific military capabilities suitable for that purpose. Is there an exception to the indistinguishability of offensive and defensive weaponry? The surprising answer is yes. As opposed to great powers (states that can put up a fight with the strongest power in the international system), world powers are states that have the wherewithal to project power anywhere in the world. They are, thus, necessarily naval powers. Also, world powers need not be great powers. For instance, during its period of primacy in trade and finance, the Netherlands was the dominant world power but it was only a minor military power on the continent. Even Britain was a pygmy on land.
As I have argued before, the high seas are a natural monopoly, owing to the existence of natural control points (Singapore, Hormuz, Suez, Gibraltar, Cape Town, Panama). Moreover, the naval balance is determined by highly capital intensive ‘capital warships’ (‘ships of the line’ until the mid-nineteenth century, ‘iron clads’ till World War I, and aircraft carriers since shortly before World War II) as opposed to gunboats which are cheaper and capable of shallow water operations. This means that only a small handful of states have the economic-financial capability of fielding a blue water navy. Even during the inter-war period (when the ratio of capital ships was fixed at 5:5:3 between the US, UK, and Japan), global commerce would’ve been impossible without the unprecedented cooperation that obtained between Great Britain and the United States. The maritime world was effectively under Anglo-American cohegemony; a situation that was anyway unlikely to last and one that probably contributed significantly to the instability of the international system. Since 1945, the maritime world has reverted to its natural state of monopoly.
If one were to pick out a random year from the past 500, the probability that one will find a naval hegemon in the system is upwards of 90%. There is usually only one world power at any given time. The existence of naval competition on the high seas is the surest sign that a world war is on the horizon. Despite the primacy of land-based military power in the global balance of power, the maritime realm is a surer indicator of instability. Naval armament by a rising power is a direct challenge to the naval primacy of a reigning world power. Such an undertaking has only ever been taken up by states that aspire to world power status. States do not undertake such a project lightly, since they can be sure of inviting the enmity of the reigning world power.
In other words, if China starts building a large blue water navy, one can infer that it intends to challenge US’ command of the seas, and hence, the international order that is built on it. For capital ships – aircraft carriers – have no other use than to project power far from home. For instance, within the First Island Chain, land-based airpower will be a cheaper and more effective means of projecting power. It would be considerably easier for China to achieve air superiority by launching its warplanes from Chinese territory, than to build and operate aircraft carriers that cost billions apiece.
During World War II, Japan and Britain fielded dozens of aircraft carriers each, while the United States fielded a hundred-and-fifty. Today, the United States has a dozen nuclear-fueled Nimitz-class aircraft carriers in service. These supercarriers are formidable power projection tools, capable of deploying nearly a hundred fixed-wing aircraft. Each of them costs $4.5 billion and is enough to patrol the entire Indian Ocean alone. The Libyan air campaign was carried out by a single carrier group. Moreover, this is a peacetime force; suitable for a benign security environment with zero strategic challengers. In the event of a prolonged challenge to its naval primacy, the United States has the industrial and economic potential to deploy perhaps a hundred of these. Does China have the industrial strength to match these capabilities? I guess we will find out. The Chinese need to be very clear-eyed about such an undertaking.
Currently, China is wisely building up its naval capabilities solely for coastal defense. Even India, with its single aircraft carrier, has a larger blue water capability. China’s GDP, at around $8 trillion, is roughly half that of US. More importantly, China is still far from being an advanced industrial power. There is a long road ahead for China.
 Mearsheimer, John J. “The gathering storm: China’s challenge to US power in Asia.” The Chinese Journal of International Politics 3.4 (2010): 381-396.
 Dobbins, James. “War with China.” Survival 54.4 (2012): 7-24.