US security promises created moral hazard that helped drive Ukraine war

The concept of moral hazard, borrowed from insurance markets, describes what happens when one party takes risks because another bears the cost of failure. Applied to international security, it suggests that allies sheltered by a powerful protector may act less prudently toward adversaries than they would if fully exposed. A new paper from the Washington-based think tank Defense Priorities argues that this dynamic has been a defining feature of the United States' relationship with Ukraine, and that the consequences have been catastrophic for Kyiv.

The Bucharest pledge and its architects

The chain of events traces back to April 2008, when NATO leaders gathered in Bucharest. The Bush administration pressed for a declaration that Ukraine and Georgia would eventually become members, overruling objections from France and Germany. The declaration was a political signal, not a military plan. Robert Gates, then secretary of defence, later wrote that the initiative was "truly overreaching" because neither Europeans nor Americans were willing to send their sons and daughters to defend either country. He concluded that NATO expansion had become a political act rather than a carefully considered military commitment, recklessly ignoring what Moscow considered its vital national interests.

William Burns, the US ambassador to Moscow at the time and later CIA director, sent a cable in February 2008 reporting that Ukrainian entry into NATO was the "brightest of all red lines for the Russian elite (not just Putin)". In more than two years of conversations with Russian figures ranging from hardliners to liberal critics, he had found no one who viewed Ukrainian membership as anything other than a direct challenge. The cable, released by WikiLeaks, also noted expert warnings that internal Ukrainian divisions over NATO could trigger a violent split, forcing Russia to decide whether to intervene, a decision the Kremlin did not want to face.

Putin's warning and the Georgian precedent

Vladimir Putin attended the Bucharest summit. According to Mikhail Zygar's account of the Kremlin court, he told Western leaders: "If Ukraine joins NATO, it will do so without Crimea and the eastern regions." Four months later, the Russo-Georgian War provided a brutal demonstration of how the moral hazard dynamic operates in practice. Georgian president Mikheil Saakashvili, emboldened by the Bucharest pledge and Western support for Kosovar independence, launched an artillery assault on the South Ossetian capital Tskhinvali. Gates later observed that the Russians had baited a trap and the impetuous Saakashvili walked right into it. Russian forces steamrolled the Georgian military and came within 40 miles of Tbilisi. The United States did not intervene.

The Georgian episode should have been a cautionary tale for both Washington and Kyiv. It showed that NATO's Article 5 guarantee extended only to members, and that the United States would not risk a great-power war for a partner outside the alliance. Georgia's path to membership stalled, and Tbilisi subsequently sought to conciliate Moscow. Ukraine, however, continued to treat the Bucharest declaration as a binding promise of future protection.

How the promise distorted Kyiv's calculations

The paper argues that Ukraine's decision-making between 2008 and 2022 was shaped by the expectation that the West would ultimately make good on its pledge. This was not irrational from a Ukrainian perspective: the European Union offered a more attractive economic and political model than the Russian sphere, and nationalist sentiment hardened after 2014. But it created a structural incentive for Kyiv to resist compromise with Moscow, on the assumption that time and Western integration would shift the balance of power. The result, the paper contends, was that Ukraine based its foreign policy on wishful thinking rather than the geography and local balance of power that would have demanded accommodation.

Barack Obama articulated the reality in a 2016 interview with Jeffrey Goldberg for The Atlantic: "The fact is that Ukraine, which is a non-NATO country, is going to be vulnerable to military domination by Russia no matter what we do… this is an example of where we have to be very clear about what our core interests are and what we are willing to go to war for." Even after the 2022 invasion triggered a massive increase in US military and financial aid, Washington has maintained a barrier against direct engagement, refusing a no-fly zone, restricting the use of supplied weapons inside Russia, and avoiding attacks on Russian early-warning nuclear systems.

The asymmetry of interests

The core of the moral hazard problem, the paper argues, is an asymmetry of interests. For Russia, Ukraine is a vital national interest; for the United States, it is peripheral. This makes any American security guarantee inherently non-credible. The US has provided most of the weaponry and has been deeply integrated into battle-planning and targeting, creating the appearance of a NATO war fought with Ukrainian troops. Yet the United States can back out at relatively low cost. Ukraine cannot. The paper describes this as Washington leaving Kyiv "holding the bag".

Kyiv has repeatedly taken actions that risk drawing the United States deeper into the conflict, demanding a no-fly zone, pressing for permission to strike Russian territory with US-supplied weapons, and reportedly attacking Russian early-warning nuclear systems. Each such step tests the credibility of the American commitment and increases the risk of direct confrontation between nuclear powers. The paper suggests this is the "reckless driving" dynamic identified by political scientist Barry Posen: a protectorate acts more provocatively because it believes its protector will ultimately save it.

Why the promises persist

If the US commitment is not credible and the risks are disproportionate, why does Washington maintain the pledge? The paper suggests several factors: bureaucratic inertia, the sunk cost of past statements, domestic political pressure, and a reluctance to admit that the post-Cold War expansion of the alliance has reached its limit. Abandoning the Bucharest promise would require acknowledging that the security architecture built since 1989 cannot be extended indefinitely without triggering the very conflicts it was designed to prevent. It would also mean accepting that Ukraine's security must be negotiated with Russia rather than guaranteed by the West.

European perspectives on the pledge

France and Germany opposed the 2008 Bucharest declaration precisely because they recognised the credibility gap. Angela Merkel later said she had blocked a Membership Action Plan for Ukraine and Georgia because she did not want to give false hope. The German chancellor's scepticism reflected a broader European view that NATO enlargement without a parallel security dialogue with Russia was destabilising. The subsequent Minsk agreements, negotiated by Berlin and Paris, attempted to manage the Donbas conflict within a framework that acknowledged Russian interests, an approach that collapsed after 2022 but which reflected a European preference for diplomatic management over open-ended commitments.

The European Union's own enlargement policy has moved more cautiously, offering a partnership perspective rather than a fast track to membership. The contrast with NATO's 2008 declaration is striking: the EU has generally avoided making promises it cannot keep, while the alliance's open-door policy has created expectations that outrun the willingness of member states to honour them. This tension between the two organisations' approaches to Ukraine remains unresolved.

What a different Ukrainian calculus might have looked like

The paper does not argue that Ukraine should have surrendered its sovereignty. It argues that a sober assessment of the local balance of power, geography, Russia's nuclear arsenal, the asymmetry of interests, and the demonstrated unwillingness of the United States to risk direct war, would have led Kyiv to pursue a different diplomatic strategy. That might have included a formalised neutrality, security guarantees from both East and West, and a negotiated settlement on the status of Donbas and Crimea. Such an outcome would have been bitter for Ukrainian nationalism. The paper contends it would have been far less bitter than the destruction inflicted since 2022.