5 September 2019 Guest blog by Professor Yong-Shik Lee is Director and Professorial Fellow of the Law and Development Institute and Hiram H. Lesar Distinguished Visiting Professor in Law, Southern Illinois University School of Law. In the last eighteen months, President Trump has re-introduced the use of national security arguments to restrict the USA’s international trade for commercial reasons. I recently warned[1] that the US use of security arguments to justify its additional tariffs on steel and aluminum imports would create a dangerous precedent, and shortly after that, another major trading nation has indeed followed this precedent. […]