The only time Article 5 (NATO's founding/core principle) has been invoked was in response to the 9/11 attacks on the US. As a result, over 40k Canadians served in Afghanistan between 2001 to 2014, the country's largest deployment since World War II. https://t.co/0p7c9syE6I— John Haltiwanger (@jchaltiwanger) December 3, 2019