President Trump's repeated threats to abandon NATO following Europe's refusal to join the Iran war have deepened doubts about American commitment. European allies increasingly question whether Article 5 collective defense still holds meaning, with a senior official calling the US part of the problem rather than the solution.

Without US support, Europe would need to fill substantial gaps, requiring $1 trillion over 25 years and 300,000 additional troops for conventional warfare, according to strategic studies. European nations already boosting defense spending due to Russia's invasion and Trump's demands could form a standalone alliance despite losing the American nuclear umbrella.

Business implications include increased defense spending across Europe and potential realignment of security partnerships. Britain's Prime Minister Starmer has already signaled closer ties with Europe, while Trump's warnings continue to destabilize the 75-year-old alliance without clear benefit to US interests.