This is a deeply contested political and philosophical question that doesn't have a single factual answer I can search for—it depends on values, historical interpretation, and perspective rather than verifiable facts. I can, however, lay out the main arguments on different sides so you can weigh them yourself.
Arguments that NATO has been a force for good:
•Deterrence and stability in Europe: NATO was founded to deter Soviet aggression during the Cold War, and supporters argue its collective defense principle (Article 5 — an attack on one is an attack on all) has prevented major wars between its members for over 75 years, an unprecedented stretch in European history.
•Collective security: It has allowed smaller European states to avoid being dominated or coerced by larger powers, and has provided a framework for democracies to cooperate militarily and politically.
•Response to Russian aggression: Many argue NATO's expansion and support for Ukraine (especially after Russia's 2014 annexation of Crimea and 2022 full-scale invasion) has been a stabilizing counterweight to Russian revisionism, protecting the sovereignty of Eastern European states.
•Humanitarian/peacekeeping interventions: NATO has pointed to operations like the Bosnia and Kosovo interventions in the 1990s as examples of using force to stop ethnic cleansing and genocide.
Arguments critical of NATO:
•Provocation thesis: Critics (including many realist scholars) argue NATO's post-Cold War expansion eastward antagonized Russia and contributed to the conditions for conflicts in Georgia (2008) and Ukraine (2014, 2022), rather than purely deterring aggression.
•Libya and Afghanistan: NATO's 2011 intervention in Libya is often cited as a case where "regime change" led to prolonged chaos, instability, and civil war rather than a positive outcome. Its long engagement in Afghanistan is similarly debated in terms of outcomes versus costs.
•Legitimacy and accountability: Some argue NATO operates with insufficient UN oversight or legal grounding in certain interventions (Kosovo in 1999 being a notable example, conducted without UN Security Council authorization).
•Alliance politics and burden-sharing disputes: Critics on various sides argue NATO perpetuates militarism, enables extended U.S. dominance over European security policy, or unfairly burdens wealthier members while free-riding by others.
My take: Whether you view NATO positively likely depends on how you weigh deterrence/stability against expansion/intervention critiques, and how you interpret cause-and-effect in conflicts like Ukraine. If you want, I can dig into a specific angle—like NATO's role in a particular conflict, the debate over its expansion, or how different countries' governments currently view it—with actual sourced research.