The U.S. has just doubled tariffs on steel and aluminum imports from 25% to 50%, a move that has ramped up pressure on global steel producers and has drawn condemnation from around the world. In Canada, the top exporter of steel and aluminum to the U.S., the Prime Minister's office called the move "unjustified and unlawful". How are nations around the world responding to the hike? How will this impact U.S. steel production and U.S. consumers? And just where is Trump's trade war heading?