Great piece by @LiamHalligan. 

"Trump's" tariffs, if introduced as advertised, would indeed amount to the most serious escalation of US protectionism since the infamous Smoot-Hawley tariffs that saw the Wall Street crash of 1929 morph into the Great Depression that lasted most of the 1930s.

Introduced by two Republicans, Senator Reed Smoot and Congressman Willis Hawley, the raft of tariffs sparked financial panic then a worldwide trade war, arguably helping to cause the Second World War. US unemployment soared from 8pc when the protectionist measures were introduced in 1930 to 25pc by 1933, with global trade flows plunging two thirds over the same period."