Earlier quoted context omitted.
Why were you skeptical of NATO membership? What are the downsides?
America runs NATO and does not have a perfect history of only getting involved in justified wars itself. Being a NATO member means that other members can drag you in to something you wouldn't join yourself. For example, NATO helped in Iraq and Afghanistan (in small ways, by supporting the US-supported local forces), which weren't going to attack France for example any time soon. What Russia has done is made the odds…
A number of NATO countries joined both Iraq wars, but not all. The only one where Article V was invoked and NATO was officially involved was Afghanistan.