Review Question
Will Ukraine become a member of NATO by 31 December 2028?
Answer | Initial Probability |
---|---|
Yes | 50% |
No | 50% |
Author

Description
NATO, the North Atlantic Treaty Organization, is a military alliance of 32 countries from North America and Europe, founded in 1949 to provide collective security against the Soviet Union (U.S. Department of State). Ukraine's potential NATO membership has been a contentious issue in international relations, particularly since Russia's annexation of Crimea in 2014 and the ongoing conflict in eastern Ukraine (NATO).
While NATO has supported Ukraine’s sovereignty against Russia’s invasion and stated that Ukraine is on an “irreversible path” to NATO membership, it has yet to extend an official invitation to join (CBS News). Ukraine acknowledges that NATO membership is unlikely while the war with Russia continues, as the alliance avoids admitting countries with active conflicts (Euractiv). However, Ukrainian leaders maintain that joining NATO is essential for long-term security, viewing the alliance’s mutual defense commitment as the only credible guarantee against future Russian aggression (Politico). Ukrainian President Volodymyr Zelenskyy has even put forward the idea of Kyiv-controlled territories joining NATO as a way to end the “hot stage” of the war (AP News, France24).
Skeptics contend that a promise of NATO membership to Ukraine would only incentivize Russia to prolong the war (Politico). Additionally, U.S. Secretary of Defense Pete Hegseth called NATO membership for Ukraine and a return to pre-2014 borders "unrealistic" goals that should not be part of negotiations to end the war with Russia (Euronews). However, Swedish and U.S. officials have emphasized that membership is still possible if conditions are met (Reuters, Reuters).
Additional Resources:
- Atlantic Council - Ukraine seeks further progress toward EU membership in 2025
- Brookings Institution - Russia-Ukraine after three years of large-scale war
- RAND Corporation - A Bridge for Ukraine into NATO
Resolution Criteria:
This question will be resolved as “Yes” if Ukraine officially joins NATO on or before 31 December 2028. For the purposes of this question, "joining NATO" is defined as Ukraine’s instruments of accession to the North Atlantic Treaty being deposited with the U.S. State Department. This step signifies the finalization of NATO membership after all member states have ratified Ukraine’s accession protocols. Recent examples of similar announcements include Finland's and Sweden's accessions to NATO.
The idea for this question was originally suggested by forecaster @Plataea479.
Starts
Feb 27, 2025 05:00PM
Closes
Jan 1, 2029 05:00AM
Topics
International Diplomacy & Conflict
Russia-Ukraine War
Tags
No tags selected
I think the discussion is excellent. Agreed with the main points:
- The question is very well formulated
- However, the content might not be very interesting as it is likely the crowd's forecast will converge around 0%
- The crux of the question might not lie in Ukraine completing the NATO accession process, but in receiving enough support to formally begin it
- As some suggested, it might be more useful to individually ask whether or not key NATO countries will support Ukraine's accession to NATO
- The same can be asked for Ukraine joining EU
As others have said, the crowd consensus would probably be <10% pretty much from the start. I don't think that's too big of a problem, though. It's inevitable that that happens to some questions, and the 0–1% forecasts are occasionally proven overconfident, which is part of the process. I would personally forecast more like 15% initially.
However, it makes sense to try to aim for as close to 50% as possible. One way this could be achieved by loosening the resolution criteria – instead of full membership, ask about an earlier step in the process. The criteria should still be strict enough that the question is meaningful, so this probably can't change the question or the probability much. A second possibility is to extend the timeframe. However, three years is already long and it's unclear how valuable longer timeframe forecasts are (plus practical problems).
Apart from these concerns, the question description, additional resources and resolution criteria seem good.
Interesting comments - My view is that probably the more important issue is Ukraine being put on the path towards NATO membership, rather than actually having to get there within the timeframe (to avoid this question being dominated by considerations of how quickly NATO and NATO-member bureaucracies can move).
This would also seem to be highly contingent upon some form of ceasefire. As such, it is almost a sub-set of the other proposed question. Perhaps the questions could/should be combined:
Let's assume the current war with Russia constitutes a huge chunk of the odds here. Since the question seems too obvious and too certain on a NO resolution, perhaps breaking the question into sub-questions could further provide value for those wondering about the main question. Here are some ideas:
Will the Russia-Ukraine war end before 2028?- Important to ask due to its main influence on the NATO ascension odds. Ceasefire and concessions may also reduce the need for membership.
Will the United States change its stance on the Ukraine war through leadership changes in the next few years?- This is important to ask because anticipating how elastic the US' supportive stance on Ukraine is crucial in gaining a proper understanding of the potential odds of Ukraine's joining NATO.
Questions regarding Ukraine's military and government style, form, effectiveness, and structure.- NATO has certain expectations to be met.
Questions regarding Membership Action Plan being initiated.- Important to assess any mentions of this as this would be the precursor for us to anticipate a NATO membership consideration.
Questions that ask about the strength of NATO/Europe in general.- I see a lot of attacks on the legitimacy of the EU and governments in Europe trending to far-right leadership, which could dismantle credibility in the alliance in the long term.
cc: @dante @FP
I agree with many opinions expressed below that this will most probably settle very quickly in the 0% to 1% range, so its actual usefulness for decision-makers is not at all clear to me (and if it is not to be useful to them, why bother?).
Now, grabbing the opportunity offered here...:
It has occurred to me lately that we may have a bias here toward publishing questions that are much more likely to be resolved as No rather than Yes (an actual data analysis would be very interesting to me); and such questions naturally attract forecasts of almost absolute certainty (~ 0%) which may be not that thoughtful (to put it mildly...), but nevertheless score only too well when scoring time comes, leaving people that appear less certain (say, in the range 5% to 15%) but much more nuanced and thoughtful with inferior Brier scores. Now of course, this is supposed to cancel out when the number of forecasting questions is big enough, but in practice even such a condition does not seem to work very well (and the sample number seems never large enough).
We are pro forecasters, and I guess that the fact that we do care about our public Brier score should not come as a surprise. I guess one of the key ideas behind this whole thing of crowdsourced probabilistic forecasting is an alignment of incentives between the question sponsor and the forecaster; based on what I have said above, it would seem to me that this incentive alignment may be actually ruptured somewhere, and it may need repair. In that light, I am not sure what one more question almost certain to settle close to 0% will actually offer to any one of the participating parties.
Just my 2 cents...
That said, I'm almost never as certain as 0% or 100%, but I don't know how the users benefit from a 5-10% or 90-95% forecast from me. Since there's a whole crowd out there working on the same questions, I think it's better to let the cum show the uncertainty rather than my individual forecast. I put my uncertainty in my rationales, and I take the "why I might be wrong" comments seriously. That allows the user to decide on their own how much they want to hedge a bet or condition a decision on uncertainty -- whether my uncertainty is 5% or 10% is of less value than my rationale (I hope). The cum should indicate how much a customer/user needs to invest in a Plan B or C or Q if there are indeed alternative decision paths. I recognize that many of my colleagues are more scientific in their forecasts than I am -- I think it's because they are filling a true analyst's role. (As @404_NOT_FOUND labeled "well-calibrated forecasting.") I tend towards taking a decision maker's role since that's been my professional upbringing and career role and I believe that's where my experience and skills lie -- make a decision but explain my rationale as clearly as possible, and cite supporting evidence.