Introduction

The 2025 NATO Summit unfolded against the backdrop of doubts about the alliance's future direction. As the first summit since the start of President Trump’s second term, it carried a heightened level of anxiety. President Trump’s numerous criticisms about European allies’ failure to meet defense commitments and comments regarding U.S. commitment to European security had fueled concerns that the Summit would put on display clear divisions within the alliance. In the weeks leading up to the Summit, there were reports that some NATO members were quietly preparing a plan on how Europe would assume greater security responsibilities so as to avoid chaos if the U.S. were to unilaterally withdraw from the alliance.¹ In addition to discussions on burden sharing, expectations were high for meaningful discussion on Ukraine, now entering into the third year of war, as well as the deteriorating situation in the Middle East, including the Israel-Hamas conflict and the recent U.S. strike on Iranian nuclear facilities. With these overlapping crises, there were doubts about whether President Trump would even attend the Summit, given his abrupt departure from the recent G7 meeting. Even if President Trump did attend, these contentious issues set the stage for a high-stakes gathering. 

All things considered, the Summit was portrayed as a success by NATO members, yielding a succinct Hague Summit Declaration that affirmed NATO’s collective defense under Article 5 and allies’ commitment to invest 5% of GDP on defense and security by 2035.² Yet beneath the carefully managed optics, fundamental concerns persist. The Summit felt less like a moment of strategic renewal and more like performative display aimed at concealing the alliance’s underlying decline. In this context, this Issue Brief examines what the 2025 NATO Summit reveals about the trajectory of the alliance as well as its implications for South Korea’s approach to alliance burden-sharing with the United States and its relationship with NATO more broadly.

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• 1.  “Europe Working on Plan to Replace US in NATO in Five to 10 Years: Report,” Al Jazeera, March 21, 2025, https://www.aljazeera.com/news/2025/3/21/europe-working-on-plan-to-replace-us-in-nato-in-five-to-10-years-report.

• 2. North Atlantic Treaty Organization, "The Hague Summit Declaration," June 25, 2025, https://www.nato.int/cps/en/natohq/official_texts_236705.htm.