#Tradewars

Markets were mulling familiar themes last week. Will a wider U.S. twin deficit change the rules for the dollar and treasuries and is elevated volatility here to stay in equities? Judging by last week, the answer would be: probably and yes.

The contemplation over these stories, though, were interrupted by politics. Mr. Trump announced his intention to apply tariffs on steel and aluminium—25% and 10% respectively—and Mrs. May attempted to give clarity on the U.K. government’s Brexit position.* I was unimpressed with both.

Before I have a dig at Mr. Trump, I ought to provide an example of someone who supports it. I have great respect for Stephen Jen, but his argument here is like endorsing the idea of a diet by advising someone to eat nothing but kale and carrots for a decade. The analysis of Mr. Trump’s tariffs requires a distinction between the principle and the concrete measures.

I concede that China is bending the rules of global trade, but Mr. Trump is stretching the fabrics of macroeconomic policy if he starts imposing tariffs on industrial goods. He is presiding over an economy close to full employment, a low domestic savings rate, and a medium-sized twin deficit. To boot, he is about to let fly with unprecedented fiscal stimulus.