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The untold story behind Ukraine’s military success

Something is missing from the story of Ukraine’s impressive military success against Russia. The preface to that success is a program called Partnership for Peace (PfP). Ukraine has been an active participant since the 1990s, an experience indispensable to Kyiv’s ability to exploit its swelling support from NATO.

PfP had conceptual roots in the administration of George H.W. Bush, but it became a serious endeavor during the Clinton and George W. Bush administrations. Proponents saw it as preferable to formal enlargement of NATO, a process that entailed extending the treaty’s Article 5 guarantee of each member’s territorial integrity.

The PfP option was central to the arguments of those who opposed NATO enlargement. A bipartisan group of senators, led by Daniel Patrick Moynihan (D-N.Y.) and John Warner (R-Va.), favored active security cooperation with former Soviet satellites but considered it neither necessary nor prudent to offer them full alliance membership. Numerous other leaders doubted the wisdom of early NATO expansion, arguing that potential Russian revanchism could be deterred by cooperation short of extending the alliance’s borders toward Moscow.

In important respects, the response to Russian aggression has vindicated both the advocates and the opponents of NATO expansion. Ukraine’s close relationship with NATO began as early as 1991 and took on more official aspects three years later when Kyiv joined PfP.  

These were more than nominal connections; they facilitated on-the-ground working arrangements between Ukrainian forces and several military establishments in NATO. The relationship evolved over the decades through various charters, councils and commissions, notably the 1997 Charter on a Distinctive Partnership. The NATO-Ukraine Commission (NUC), reinforced by additional agreements in 2009, oversaw a wide range of planning, training, table-top exercises and, most importantly, significant operational collaboration.


For more than 20 years, a NATO liaison office promoted modernization of Ukrainian capabilities and their interoperability with allied forces. Those efforts were often bilateral, so that Ukrainian officers and troops formed close relationships with their neighbors.

Nor was the engagement a one-way affair. Ukraine assisted NATO peace-keeping initiatives in the Balkans, including deployment of a heavy engineering unit in Kosovo. It took part in the multi-national attempts to stabilize Afghanistan, providing valuable overflight rights and sending medical personnel and instructors to help that nation’s struggling military. Ukrainian officers were part of the NATO training mission in Iraq, and Ukrainian ships deployed repeatedly to support counter-terrorist and anti-piracy surveillance in the Mediterranean.

This web of practical PfP activities meant that when Russia mounted its major invasion in 2022, Ukraine was prepared to make good use of NATO support.

Ukraine’s battlefield success also owes much to the readiness of nearby NATO members – especially Poland and the Baltic states – to bolster Kyiv. They and other alliance partners have absorbed the enormous flow of refugees from the war and have been vehement advocates of supplying better weapons to Ukraine.  

NATO enlargement transformed the neighborhood. Kyiv found ardent supporters in NATO governments that joined the alliance as part of that process. Those states are, of course, the ones most sensitive to the dangers of Russian aggression. Even if they were not NATO members, their interest would lie in backing Ukraine and thwarting prospects of future Russian aggression. Their membership, however, greatly enhanced their influence in shaping the alliance’s posture toward the war.

This context would be incomplete without noting Russia’s own relationship to NATO. The collapse of the Soviet Union altered the European security landscape so fundamentally that it was essential to design a new structure for stability. NATO proved to be the cornerstone, but it sought in good faith to include Russia. In 1997 the NATO Russia Founding Act framed a set of constructive principles for the relationship, and Russia, too, soon joined the PfP. 

During a more hopeful period, then-President Dmitri Medvedev was asked whether Russia might in fact become a member of NATO. He said the offer had not been made, but “one should never say never.” Russia sharply opposed U.S. bombing of Serbia, but there was also significant cooperation, highlighted by Moscow’s transport of non-military freight for the international intervention in Afghanistan.  

Sadly, those benign links faltered. Moscow read NATO’s arrangements in Central Europe as hostile, rather than defensive. Captive to Vladimir Putin’s fears and ambitions, Russia made itself the outcast it need never have been. 

Alton Frye is the Presidential Senior Fellow Emeritus of the Council on Foreign Relations.