For meta-historians who take the long view, e.g. Arnold Toynbee, there is the emergence of a "looming global peace" that is gaining acceptance in the corridors of Academe. It is predicated on the belief that we are nearing a point in history where war as we know it has disappeared. Presumably the world is becoming safe and secure with few violent conflicts. Moreover, the United States faces no plausible existential threats or great power rivalry. This is the unvarnished theme at its most basic level.
There is evidence to support it. Since 1946 armed conflict across the globe, including deaths in battle, have declined precipitously. There are zones of peace such as Europe which throughout the last 400 years have known nothing but war. Most of the conflicts that do occur are intra-national rather than an imperial desire for empire. Even China's view of the Middle Kingdom does not overlook the sovereignty of its Asian neighbors. And there is Frank Fukuyama's belief we have reached the "end of history," a point at which the rivalry among nations is eliminated.
That this world view is in the ascendency is not surprising. It is consistent with the Obama position that fewer forces than we now deploy will be required on the battlefield and, while military hardware is still necessary, being armed to the teeth is an unnecessary expenditure of scarce resources. This isn't Kellog-Briand all over again, but it is a distant cousin of the proposition war as we've known it will not be seen again.
While evidence for these claims cannot be casually dismissed, they are hardly dispositive. The Chinese are not likely to be satisfied with a military force about a fourth the size and strength of the United States. Deployment of the Chinese navy in the South China Sea and the Sea of Japan has already raised alarms in Japan and the Philippines. Putin's Russia has ambitions to reclaim areas lost with the fall of the Soviet empire and to reassert his influence in east Europe.
Arguably the most serious challenge comes from the Islamic radicals intent on creating caliphates across the globe. Since these radical groups comprise many non-state actors opposing and defeating them is increasingly complicated. Moreover, it is conceivable that nuclear weapons can be secured by these groups disrupting any form of stability.
Then there are the Shia imams in Iran who believe nuclear weapons offer leverage over Sunni rivals in the region. The quest for nuclear capability is both a political and military weapon that could give Iran leverage as a Middle East power to be reckoned with.
Nuclear weapons themselves could alter the balance of power in any region of the globe. Since proliferation is likely to occur in both nuclear weapons, and other forms of lethality it isn't clear if nations with these weapons promote stability or the possibility weapons of mass destruction will be employed.
The diffusion of technology and the influence of information available in real time alter the notion of international equilibrium. It is possible that uneven economic development, an aging workforce, widespread urbanization, unemployment and demographic perturbations could result in areas of instability and the rise of extremist political parties.
As a backdrop, the withdrawal of the U.S. from its post World War II role as international balance wheel and frayed alliance resilience are opening vast unknowns on the world stage. Since political vacuums are always filled, there are many imponderables, including many dangerous outcomes that await us. Resource competition and socio-economic stress must be added to the scenario mix as potential sources of conflict, albeit innovations such as fracking could mitigate the resource concern.
Since the future is not foreseeable and human nature not predictable or linear, the only guide to the future is the past and that too is not a reliable guide since history does not repeat itself exactly. Even if emergent trends suggest zones of peace, they do not insure order and stability. War has not stopped evolving and whether we like it or not, all forms of warfare from terrorism to major combat are possible. Therefore it is best to prepare for the worst and hope for the best. Recent history isn't a definitive guide for defense allocations. And the Obama administration belief that the bulk of budget reductions through sequestration can be imposed on defense spending is potentially very dangerous.
Writing about his belief in God, Blaise Pascal made the point that if you believe in God, but He doesn't exist, all you've done is wasted time. But if there is a God and you do not believe in Him, you have sacrificed everything. Applying this notion to security, it is obvious if war is still a possibility and you do not believe in preparing for it, you will have sacrificed everything - your future, your liberty, your nation. Hence skepticism about the school of emergent global peace is a healthy response.