This week President Trump's promises of tariffs became a reality, with universal levies on aluminium and steel imports becoming a reality. The EU responded with their own tariffs on items from bourbon to jeans and the mayor of Ontario threatened to turn of electricity supplies to the US.

Caitríona Perry, Sumi Somaskanda and Bernd Debusmann offer insight and analysis on another whirlwind week in Washington DC.

Producer: Aisling Taylor