So I guess 2016 claimed its biggest victim yet - America

In terms of actual treaty commitments, they are not. The 2% figure is not part of the treaty, it’s a long-term commitment under the Riga summit declaration of 2006, reinforced with a 10 year target in 2014. The only current commitments arefor those with spending over 2% now to not let it fall below 2%, and for those below 2% with declining spending to halt the decline. And even those are not technically treaty obligations, but political guidelines.