Another week, another wave of sabre-rattling from the Trump administration over trade. Two months ago, it was softwood lumber that grabbed the headlines: Wilbur Ross, US commerce secretary, announced tariffs on Canadian wood imports, arguing these were undercutting American rivals.

Now the focus is on steel. In the coming days Mr Ross is expected to issue a report outlining how cheap steel imports from countries such as China are hurting US companies, and undermining “national security” and jobs. This may well lead to US tariffs on steel — a threat that has already sparked an outcry from other world leaders, including Germany’s Angela Merkel.

It is unclear how sweeping any tariffs will really be. But one thing is clear: White House officials urgently need to read some timely analysis from the Bank for International Settlements about the issue.