This is a question about values and geopolitics where reasonable people disagree, so let me share some perspective rather than a definitive verdict.
Arguments that NATO has been a force for good:
•It's a defensive alliance (Article 5 is mutual defense, not aggression) that has helped deter major interstate war in Europe since 1949—no NATO member has been invaded by another state during that time.
•It provided a framework for former Eastern Bloc and Soviet states to integrate with the West after the Cold War, which many of those countries actively sought as protection against Russian aggression.
•Its response to Russia's invasion of Ukraine—coordinating military aid, sanctions, and support for Ukrainian sovereignty—is seen by supporters as defending the principle that borders shouldn't be changed by force.
•It has enabled smaller European states to avoid re-arming heavily or falling under great-power domination.
Arguments critical of NATO:
•Its 1999 intervention in Kosovo and 2011 intervention in Libya are cited by critics as examples of overreach beyond a purely defensive mission, with Libya in particular widely seen (even by some former Western officials) as leading to state collapse and chaos.
•Some scholars (realists like John Mearsheimer) argue NATO expansion eastward after the Cold War provoked Russia and contributed to the conditions for the Ukraine war—a view others strongly dispute, arguing it lets Russia off the hook for its own choices.
•Critics on the left and right sometimes argue NATO extends U.S. military dominance and draws member states into conflicts (e.g., Afghanistan) that weren't clearly about their own defense.
•Questions persist about burden-sharing, with the U.S. historically covering a disproportionate share of costs, and debates about the alliance's purpose and cohesion continuing today.
My take: Whether you view NATO as "good" often depends on which values you weight most—collective security and deterrence versus non-intervention and skepticism of military alliances, or a European/Eastern European perspective (where NATO is often seen very favorably) versus a non-Western or restraint-oriented foreign policy perspective (where it's viewed more critically).
Would you like me to dig into a specific aspect—like its role in the Ukraine war, its founding purpose, or comparisons to other security arrangements—since NATO's current relevance is a live and evolving topic?