NATO has expanded substantially since the Cold War — Finland (2023) and Sweden (2024) are recent additions. Article V (mutual defense) has been invoked once, after 9/11. Recent debates:
- Burden-sharing: U.S. spends ~3.4% of GDP on defense; many European allies still below the 2% benchmark, though most have increased post-2022.
- Article V scope and credibility: How clearly does U.S. commitment extend to all members?
- NATO expansion / Ukraine path: Membership prospects for Ukraine, Georgia.
- Indo-Pacific: Bilateral alliances (Japan, Korea, Philippines), AUKUS submarine pact, the Quad.
- Treaty-style commitments: Whether modern alliances should require Senate ratification.