FILE - NATO country members flags wave at NATO headquarters in Brussels, on Nov. 28, 2023. Twenty-three of the alliance's 31 non-U.S. members will meet or exceed their commitment to spend at least 2% of economic output on defense this year, up from just three 10 years ago, according to figures compiled by NATO. (AP Photo/Geert Vanden Wijngaert, File)
FILE - German Chancellor Olaf Scholz, left, visits the German Federal Armed Forces Bundeswehr mountain infantry brigade in Schneizlreuth, southern Germany, on July 22, 2024. With Trump's "America First" rhetoric drawing cheers from fervent supporters, the future of the North Atlantic Treaty Organization is once again on the agenda. (Alexandra Beier/Pool Photo via AP, File)
FILE - Chinese President Xi Jinping, left, and France's President Emmanuel Macron review troops during a welcome ceremony at the Great Hall of the People in Beijing, China, on April 6, 2023. France's President Emmanuel Macron has urged European nations to seek more independence on airspace defense and relocate production to the continent rather than purchasing material off the shelf from American arms merchants. (AP Photo/Thibault Camus, File)
FILE - Eurocopters Tiger of the German Army take part in the Lithuanian-German division-level international military exercise 'Grand Quadriga 2024' at a training range in Pabrade, north of the capital Vilnius, Lithuania on May 29, 2024. NATO's military structure is headed by the Supreme Allied Commander Europe, who is also the commander-in-chief of American forces in Europe. (AP Photo/Mindaugas Kulbis, File)
FILE - NATO Secretary General Jens Stoltenberg, right, directs U.S. President Donald Trump which way to step off the podium at a welcoming ceremony during a NATO leaders meeting at The Grove hotel and resort in Watford, Hertfordshire, England, on Dec. 4, 2019. When Donald Trump suggested during the 2016 presidential campaign that he might not honor a U.S. commitment to defend other NATO countries if they were attacked, it triggered alarm throughout the trans-Atlantic alliance. (AP Photo/Francisco Seco, File)
FILE - A transport helicopter carries an artilery piece of the United States 101 Airborne Division run during an exercise at the Mihail Kogalniceanu Air Base, near the Black Sea port of Constanta, Romania, on March 31, 2023. Trump's threat to renege on NATO's collective security guarantee, a cornerstone of the alliance, is based on his belief that member states aren't living up to their funding commitments, forcing U.S. taxpayers to subsidize Europe's defense. (AP Photo/Vadim Ghirda, File)
FILE - Italian Air Force Eurofighter Typhoon military fighter jets participate in NATO's Baltic Air Policing Mission operate in Lithuanian airspace, on Sept.12, 2023. NATO grew out of secret talks among U.S. officials after World War II about how to supply military equipment to Western Europe and ensure a coordinated response to any attack by the Soviet Union. (AP Photo/Mindaugas Kulbis, File)
FILE - German soldiers take part in the Lithuanian-German division-level international military exercise 'Grand Quadriga 2024' at a training range in Pabrade, north of the capital Vilnius, Lithuania on Wednesday, May 29, 2024. After relying on U.S. leadership of NATO to protect them for the past 75 years, European nations must take on a larger role in funding and leading the 32-nation alliance because their interests are increasingly diverging from those of the United States. (AP Photo/Mindaugas Kulbis, File)
FILE - Britain's Royal Navy patrol ship OPV "Trent" attends the Sea Breeze 2021 exercise in the Black Sea, on July 8, 2021. Trump's skepticism about NATO was underlined last week when he named Vance as his running mate. Vance opposes U.S. support for Ukraine, has criticized European nations for slashing defense spending since the Cold War, and said it's time for "Europe to stand on its own two feet." (AP Photo/Efrem Lukatsky, File)