The 50 per cent U.S. tariffs on billions of dollars of Canadian goods are now in effect, and Prime Minister Mark Carney is vowing dollar-for-dollar retaliation after trade talks collapsed. The House looks at what went wrong and what another escalation could mean for Canada. Plus, could Canada become the world's breadbasket? Experts debate whether Canada should boost its global agri-food exports or focus on food security at home. »»» Subscribe to CBC News to watch more videos: http://bit.ly/1RreYWS For breaking news, video, audio and in-depth coverage: https://www.cbc.ca/news Follow CBC News on TikTok: https://www.tiktok.com/@cbcnews Subscribe to CBC News on Snapchat: https://bit.ly/3leaWsr Subscribe to CBC News on WhatsApp: https://www.whatsapp.com/channel/0029Vb6MSjH9Bb63S9tbQa1Y Download the CBC News app for iOS: http://apple.co/25mpsUz Download the CBC News app for Android: http://bit.ly/1XxuozZ »»»»»»»»»»»»»»»»»» For more than 80 years, CBC News has been the source Canadians turn to, to keep them informed about their communities, their country and their world. Through regional and national programming on multiple platforms, including CBC Television, CBC News Network, CBC Radio, CBCNews.ca, mobile and on-demand, CBC News and its internationally recognized team of award-winning journalists deliver the breaking stories, the issues, the analyses and the personalities that matter to Canadians.