A fresh trade deal between Washington and Tokyo, with Japan pledging investments in the US and opening up its long-protected agricultural sector in exchange for lower tariffs, underscores how even long-standing US allies are not shielded from President Donald Trump's "America first" push to reshape the global trade paradigm,

The president’s vision for reshaping global trade is falling into place, but he is embarking on an experiment that economists say could still produce damaging results.