The US will not abandon NATO but is currently pressuring members to finally pony up their fair share towards group defense in their budgets, something they have failed to do since NATO inception. The US has paid the bill ever since WWII and it is fair time for those countries to balance their budgets correctly for their own defense as agreed to in the NATO charter. But I am 100% convinced the US would not ignore a Russian attack on NATO and keep its military assets sequestered on the sidelines just to watch the other NATO countries squirm and struggle against Russia. This would be completely idiotic and would increase the risk of a desperate deployment of nuclear weapons by European countries for survival which would only incentivize Russia to tap its own massively larger nuclear forces against Europe. From one USNA grad to another, I believe this is a naive assessment of the NATO situation and reflects simplistic understanding driven by conventional thinking that prevailed during WWII - before nuclear weapons existed.