In the autumn of 2026, Washington finds itself at a crossroads that every great trading civilization has eventually faced: the temptation to turn inward, to wall off exchange in the name of protection, and the ancient economic truth that such walls tend to impoverish those they shelter. The Trump administration is pressing for sweeping tariffs and potential severance of trade ties with Europe, insisting that prices are already falling and that further restrictions will deepen that relief. Economists across the ideological spectrum are warning, with unusual unanimity, that the historical record