Then, you'd say "nevermind, I'd rather spend it on my own armed forces," and you arrive back at NATO.
Of course? That's the entire point of it isn't it? NATO is primarily about "dragging the United States into European war" if you want to phrase it that way, though equally the point is that the threat of doing so prevents a European war involving alliance members in the first place. But the USA is at absolutely zero risk of direct invasion by Russia (or China for that matter). America is the only nation on the planet right now with any significant conventional power projection and logistics capability. NATO members all certainly kind of hope America would nonetheless come anyway.
Along with that is the risk that they'd be called on in turn, so that's a tradeoff but an obvious and straightforward one. When you sign up for insurance, you constantly must pay even if you never collect. Indeed most people very much hope never to need to collect. Hedging against black swan events costs money with by definition a low likelihood of return, but can be worth it anyway at a high enough cost (particularly since the insurers themselves have incentive to prevent rather then react).
Similarly their use of International Criminal Court for non-americans followed by claims that the ICC should not be used as it is not-elected when America has been caught committing war crimes.
America has not done a whole lot to help its own reputation in these matters :-/
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.
What Russia has done is made the odds of NATO dragging you in to something (which hasn't really ever happened in a major way) look much smaller than the odds of them invading you (which is happening to a NATO nonmember today).