This question calls for a normative judgment rather than a factual lookup I can resolve through search—it's fundamentally a matter of political philosophy, values, and perspective rather than something with a single verifiable answer. Different people reasonably disagree based on their views on security, sovereignty, history, and international relations. That said, I can lay out the substantive considerations people raise on different sides, and you can weigh them yourself.
Arguments that NATO has been a force for good:
•Deterrence and peace among members: NATO is a military alliance of 32 countries in Europe and North America, and proponents argue its collective defense principle (Article 5 — an attack on one is an attack on all) has prevented major war among its members for over 75 years, which is historically unusual given centuries of European conflict.
•Stabilizing post-Cold War Europe: Supporters argue NATO expansion gave newly democratic Eastern European states security guarantees that helped them consolidate democracy and avoid Russian domination.
•Collective response to aggression: Its backing of Ukraine since 2022 is framed by supporters as defending the principle that borders shouldn't be redrawn by force.
•Crisis response: NATO has conducted humanitarian and peacekeeping missions (e.g., Balkans in the 1990s, anti-piracy operations).
Arguments that NATO's record is mixed or harmful:
•Provocation thesis: Critics (including some realist scholars like John Mearsheimer) argue NATO's eastward expansion after the Cold War needlessly antagonized Russia and contributed to the conditions for the Ukraine war, despite informal assurances some say were given about non-expansion.
•Interventions of questionable legality/outcome: The 1999 Kosovo bombing campaign lacked UN Security Council authorization, and the 2011 Libya intervention is widely seen as having left behind state collapse and chaos rather than stability.
•Democratic accountability concerns: Some argue NATO entrenches US military dominance over European foreign policy and locks members into costly, US-aligned military postures regardless of their populations' preferences.
•Opportunity cost: Others question whether resources devoted to NATO military spending could be better used, or whether the alliance's existence itself perpetuates a logic of militarization rather than alternative security architectures (e.g., collective security through the UN or OSCE).
A reasonable synthesis: Most serious analysts land somewhere between "NATO is an unambiguous good" and "NATO is simply harmful"—recognizing it has provided real security benefits to its members while also making choices (expansion, specific interventions) that are legitimately contested on strategic and moral grounds.
Where do you fall on this, or is there a specific aspect—like the expansion debate, a particular intervention, or its role in Ukraine—you'd like to dig into further?