Ukrainian officials are pounding the drumbeat for full NATO membership, putting unrelenting pressure on the U.S. and allies to give in and view as precedent their success in receiving F-16 fighter jets, Western tanks and other heavy artillery over Western caution. 

It’s a long-shot bid and likely to take years to realize, but Ukrainian officials are focused on getting the West to offer concrete commitments at the alliance’s leaders-level July summit in Vilnius, Lithuania. 

“Ukraine’s path to NATO and a political invitation to accession should be developed in the context of preparations for the Alliance Summit in Vilnius already,” Ukrainian President Volodymyr Zelensky said during a nightly address to the nation last week. 

“The time for integration and security certainty has obviously come …”

But a major hurdle for Ukraine’s accession — which critics and supporters have pointed out — is that a prospective state cannot be engaged in active conflict. 

“As a practical matter, I don’t see how you can bring a country that’s currently under invasion by another into NATO,” Mary Beth Long, a former assistant secretary of defense for international security affairs, said during a panel hosted last week by the Leadership Council for Women in National Security. 

“Just with the apparatus of NATO, Article 5, there are so many implications,” she continued, referring to the terms of the mutual defense pact of the alliance stating that an attack on one is an attack on all.

It’s a concern that alliance members are fielding, with NATO Secretary General Jens Stoltenberg saying on Monday the focus is on “how to move Ukraine closer to NATO,” but a formal invitation or commitment would not be issued in Vilnius. 

Ukrainian officials are frustrated with the semantics. 

“Ukrainian society as a whole, and ourselves as the Ukrainian leadership, we expect during the NATO Summit in Vilnius this summer, we shall hear something more specific and concrete rather than ‘the doors of NATO remain open for Ukraine,’” Ukrainian Prime Minister Denys Shmyhal said in an interview with The Hill in April. 

Ukrainians and their supporters say there are practical steps NATO can take short of offering Kyiv full membership, with strong rhetoric and blunt commitments viewed as essential weapons in the political battle against Russian President Vladimir Putin.

“If you make security guarantees and NATO membership dependent on cessation of hostilities, you are giving Putin an incentive to continue the war,” Anders Fogh Rasmussen, a former secretary general of NATO, said during an event hosted by the Atlantic Council.

Rasmussen co-authored an action plan with Zelensky’s senior adviser, Andriy Yermak, laying out how NATO members and other supporters could establish tangible security guarantees for Ukraine on the pathway to membership, while also reassuring nervous allies concerned over provoking Putin to nuclear escalation.

While Baltic states bordering Russia — Lithuania, Latvia and Estonia — have issued clarion calls for Ukraine to immediately join the alliance, other European leaders are more cautious.

German Chancellor Olaf Scholz, standing next to Stoltenberg during the press conference on Monday, said they “need to focus on the task at hand” and pointed to NATO’s declaration at Bucharest in 2008 that acknowledged Ukraine’s aspiration to join the alliance and laid out a Membership Action Plan (MAP) to lead to its accession.

But Ukrainian officials and their supporters are calling the Bucharest declaration worthless.  

“The 15-year shadow ban on Ukraine must come to end, or otherwise, Putin will get a huge bonus for his next presidential term, which is next year, they have the elections,” Yermak said at the Atlantic Council.

Rasmussen called the 2008 Bucharest agreement a “mistake” but said getting all 31 of NATO’s members to agree on such a proposal at Vilnius is far-fetched. 

“My impression is that there will be no consensus,” he said. 

There’s also no consensus in the U.S. Congress.

While 13 Senate and House lawmakers, members of the Helsinki Commission, are calling for Biden to offer Ukraine a “clear and achievable pathway to membership, alongside robust security commitments” at Vilnius, other lawmakers are less declarative.

“First, I think there’s a lot of work to do to figure out what the right path is for Ukraine to go to NATO,” Sen. Thom Tillis (R-N.C.) told The Hill. 

“There’s a complexity that everybody I think misses out — it only takes any one member to veto, and I think there are NATO members that, in order to satisfy and get unanimous agreement for their invitee status, let alone accession, we have a lot of work to do, but I think that should be an end goal.”

Tillis, co-chairman of the Senate NATO Observer Group, introduced with his counterpart Sen. Jeanne Shaheen (D-N.H.) a resolution Wednesday reaffirming U.S. security priorities for the summit in Vilnius but held back on bluntly calling for Ukraine’s accession or security guarantees. 

Instead, it has the Senate emphasize “that the Alliance should continue to support Ukraine as it fights for freedom, sovereignty, and territorial integrity.”

A more immediate concern for 29 members of the alliance is stonewalling by Turkey and Hungary over Sweden’s accession. That nation’s application to the alliance — along with Finland — was fast-tracked in the wake of Russia’s full-scale invasion in February 2022.

Hungary has held back ratifying Sweden’s accession in retaliation for perceived insults from Stockholm against Hungarian Prime Minister Victor Orban. And Turkey complains that Sweden has failed to address its serious concerns about Kurdish militant groups. The Biden administration is dangling a weapons package to include upgrades for its ailing F-16 fighter jets as an incentive to allow Sweden’s accession to proceed. 

“I want to support Turkey — on F-16 sales, a number of other things … none of that discussion [with Turkey] occurs until we welcome Sweden into NATO,” Tillis said.