Finland has urged U.S. officials not to describe future security pledges to a postwar Ukraine as “Article 5-like,” implying that doing so could undercut the mutual defense clause at the heart of the NATO military alliance, according to a State Department cable obtained by POLITICO.

The Jan. 20 cable hints at worries in some corners over the labels used during peace talks between Kyiv and Moscow. They show how sensitive some phrases can be in the national security realm, even when officials are merely trying to offer an analogy to various audiences.

According to the cable, sent from the U.S. Embassy in Helsinki to Washington, Finnish Foreign Minister Elina Valtonen discussed the issue on Jan. 19 with U.S. Reps. Jack Bergman (R-Mich.) and Sarah Elfreth (D-Md.), both of whom are members of the House Armed Services Committee.

Valtonen underscored Finland’s view that Russia is a “long-term strategic threat” and cautioned against a “weak” peace deal for Ukraine that would hinder its ability to defend itself against future Russian aggression, the cable states.

But Valtonen cautioned against any suggestions of “Article 5-like” security guarantees in a postwar Ukraine, the cable adds. She warned that it risked conflating NATO’s Article 5 guarantees with whatever bilateral promises are made to Ukraine. It also quotes her as saying there should be a “firewall” between NATO and future security guarantees to Ukraine. Finland’s defense minister made similar points in a later meeting, according to the cable.

Article 5 is a critical clause in the NATO pact that means an armed attack on one member of the 32-member alliance will be treated as an attack on all members. NATO has invoked the article only once: after Islamist terrorists attacked the U.S. on Sept. 11, 2001.

The documents’ contents offer insight into concerns voiced by other Finnish leaders who have said that, while they want to help Ukraine protect itself, the concept of a security “guarantee” is a more serious matter they’re not ready to agree to just yet.

A Finnish official said Valtonen’s office wouldn’t comment on confidential discussions, though underscored Helsinki’s long-standing goal of eventually accepting Ukraine into the NATO alliance.

“Finland’s objective is to ensure that Ukraine receives the strongest possible security arrangements and guarantees in support of a sustainable and lasting peace,” the official said, who was granted anonymity to speak about sensitive policy matters. “Finland’s position is that Ukraine’s future lies within NATO.”

Former NATO officials and analysts said the cable reflects growing concerns in various capitals about how engaging with a postwar Ukraine could affect individual countries in the long run.

One potential problem is that “using the term Article 5 in other contexts implies NATO involvement that is not in fact a part of any of these proposed arrangements,” said Edward Wrong, a former NATO official. “Finland and many other NATO members want to ensure it is understood that Article 5 is unique to NATO.”

The State Department declined to comment.

Elfreth, one of the U.S. lawmakers Valtonen met with, did not address the session with the Finnish foreign minister directly, but said in a statement: “From our many meetings, it was clear to me that our NATO allies, new and old, are committed to advancing shared goals of defending our partners from Russian and other adversarial influences.

Bergman declined to comment.

Using Article 5 as a parallel has multiple upsides and downsides, especially given the range of attitudes toward Ukraine in NATO, the former officials and analysts said. That’s further complicated by the likelihood that individual countries, or select groups of countries — but not NATO itself — will offer Ukraine security aid in the near future.

One challenge is that by referring to Article 5, even with the “like” attached to it, national leaders could hand political ammunition to opposition groups, said Josh Shifrinson, a scholar with the University of Maryland, College Park, who advocates for a more restrained foreign policy.

There’s also the possibility that framing a security pledge to Ukraine as “Article 5-like” will entice Russia to test what that truly means.

If Russia stages some sort of an armed attack and the countries backing Ukraine struggle to respond, that could raise questions about the strength of NATO’s Article 5, said Rachel Ellehuus, a former Biden administration Defense Department official assigned to NATO.

On top of that, other members of NATO, especially those in Europe, are acutely aware of President Donald Trump’s dim views of the alliance. They are reacting to his demands that they step up defense spending and have taken on the lion’s share of aid to Ukraine. Given economic uncertainties in the years ahead, just how much they can support Ukraine is in question.

“I’m guessing the Finns don’t want to overpromise and under-deliver,” Ellehuus said.

Spokespeople for NATO declined to comment.

Finland is one of NATO’s newest members, having joined after Russia launched its full-scale invasion of Ukraine in 2022.

The Finnish foreign minister comes across in the cable as tough on Russia, a country with which Finland shares an 830-mile border.

“We should not be naïve in thinking they will change, especially if sanctions get [lifted]” and Russia becomes “empowered politically and economically,” Valtonen is quoted as saying.

Although there are ongoing talks among the U.S., Ukraine and Russia in various formats, Russian leader Vladimir Putin has not committed to a substantial cease-fire and has made demands that many Ukrainians consider unacceptable for a peace deal.

Victor Jack contributed to this report from Brussels.