The bloody intensification of fighting in eastern Ukraine has once again revived the debate over providing lethal defensive weapons to Kiev in its fight against Russian-backed rebels. The provision of such lethal assistance, were it to be undertaken, would represent a dangerous step down a slippery slope fraught with unintended — and potentially disastrous — consequences.
This argument — that the United States must counter Russian support for the rebels by arming Ukraine — was most recently articulated in a joint report issued Monday by the Atlantic Council, the Brookings Institution, and the Chicago Council on Global Affairs.
The report, authored by eight influential former policymakers, argues, "The West needs to bolster deterrence in Ukraine by raising the risks and costs to Russia of any renewed major offensive. That requires providing direct military assistance — in far larger amounts than provided to date and including lethal defensive arms."
This statement demonstrates a misguided logic that fails to grasp the realities of the current balance of power in Ukraine as well as the unintended — but entirely predictable — chain reaction that such a policy will set off.
At the heart of the matter sits what is known in international relations theory as the "security dilemma." Many of the means by which one state increases its security decrease the security of other states.
This elegantly simple concept forms the bedrock of the realist tradition of international relations, whose fundamental insight is that all states seek to be secure, but security is zero-sum: More security for me means less security for you.
From this insight stems the logic of balance-of-power politics in the international system as great powers like Russia, the United States, China, and others compete for power, security, and, ultimately, survival.
The concept of the security dilemma was further refined in the influential work of Robert Jervis, a renowned scholar of international relations, who identified conditions under which the security dilemma would be especially severe. Under these conditions, the situation would be "doubly dangerous" with competing great powers locked in a spiraling struggle for security.
Each move would force a countermove, producing an escalating arms race of ratcheting tensions that could produce the proverbial "powder keg" that could ignite with a single spark. Europe on the eve of World War I in 1914 is often used as the exemplar of this scenario.
If it is difficult to tell whether your adversary is adopting a defensive or an offensive posture, the survival imperative dictates that you assume aggressive intentions in your adversary and arm yourself accordingly.
The reality is that most lethal weapons can be used for both offensive and defensive purposes. This is certainly true of the anti-tank missiles that the above-quoted report advocates delivering to Ukraine. Similarly, the reconnaissance drones advocated in the report can be used to identify targets for offensive operations as well as defensive operations.
Thus, the caveat that the United States would provide only defensive lethal weapons to Ukraine in its fight against the rebels is a hollow one.
In a world where such weapons can be used for offensive as well as defensive operations (regardless of stated intent), such assistance is likely to exacerbate the security dilemma and could create the "doubly dangerous" powder keg in the region that could draw the United States into the conflict far deeper than it had ever imagined.
A long track record suggests that President Vladimir Putin views the world in realist balance-of-power terms. Where Russia's core security interests have been threatened he has responded in vigorous defense of those interests.
While the West may claim that NATO expansion, missile defense, European Union membership for post-Soviet states, or support for the Maidan movement are not aimed against Russia, the reality is that Moscow sees these events as threats to its core security interests.
Its current intervention in Ukraine, while a gross and unjust violation of international law, nonetheless adheres to a much older principle, that of balance-of-power politics.
There is absolutely no reason to doubt that Putin would view American military aid to Ukraine in the realist terms that have guided his foreign policy decision-making for years.
Through the logic of the security dilemma and the fallacy of "defensive-only" weapons, Putin will see this as a direct threat and will be compelled to escalate the conflict by increasing lethal assistance to the rebels. The ratchet clicks dangerously closer to a wider proxy war fought by armed agents of Moscow and Washington, one that will be increasingly difficult to contain.
The argument that arming Ukraine will serve as a deterrent to further Russian intervention is a fundamentally flawed one, ignoring the most basic reality of international relations: Great powers have interests and will defend those interests resolutely and forcefully if they deem it necessary. This is especially true when security threats arise close to the homeland.
This leads us to an uncomfortable reality: Russia cannot be deterred in Ukraine under the present circumstances. Moscow has defined the future orientation of Ukraine as a fundamental security interest for Russia.
The intensity of this attachment is far greater than Washington's attachment to Kiev. Moscow will always be willing to commit more blood and treasure to defending this interest than the West. Furthermore, Russia will be more effective at doing so due to its proximity to the conflict.
Unconstrained by any notions of "defensive-only" weapons, Moscow can more easily arm the rebels and even introduce active duty Russian forces into Ukraine when necessary. At best, the West can provide limited weaponry to a Ukrainian military that faces fundamental issues with corruption, competence, loyalty and resolve.
Such a fighting force, even armed with American drones and anti-tank missiles, could never defeat a force backed by the might — and will — of the entire Russian military. An adversary that knows it will win is an adversary that will not be deterred. To believe otherwise is dangerously wishful thinking.
The reality of balance-of-power politics is that Russia will have its way with Ukraine for the foreseeable future. There is very little that the West can do to change the equation unless it is willing to intervene directly in the conflict, something that is both terrifying to contemplate and mercifully improbable.
Ukraine's fate under Russia's fist is offensive to our most basic beliefs in sovereignty, justice and liberty, but that does not erase the fact that we are limited in our ability to rectify such injustice. That is, to borrow the phrase coined by another renowned scholar of international relations, John Mearsheimer, the "tragedy of great power politics."