European or non European nations don’t have to get into a hot war with the US to affect and sway outcomes, it simply has to announce plans to call in debts, sell bonds, stop buying bonds, replace the dollar as a trade/international currency, recall any stored gold in the US treasury, implement trade agreements with nations outside the us while announcing embargoes on US goods, tariff necessary goods from the US to force their nationals to find alternatives or reduce use.
That would throw the US into a full blown depression and would reduce capabilities to manufacture weapons and goods for general public use so hard the US would be forced to capitulate to demands for withdrawal from any NATO nation.