They arrived in a manila package at our Calgary home one day, sometime in 1956. Our family gathered around as Dad pulled out the architectural drawings and laid them on the table. They were plans for how to construct and stock a bomb shelter in case of an atomic war. A large silver siren located on top of a long white pole occasionally reminded us of that fact, as occasionally it would emit a practice wail in preparation for the real thing.For an entire generation of Canadians, none of this is strange. The Cold War was actually heating up and the threat to human existence always seemed to hang precariously in the balance. Popular music and movies were always there to remind us of the threat. The euphoria of the end of the great global conflict in 1945 didn't last long, as both the Soviet Union and the United States made their fearful moves for world domination. But the decades following took on something of a standoff between the superpowers until the Soviet Union collapsed some 25 years ago. The era of a renewed internationalism began, along with a boost in confidence for a more peaceful future.Suddenly the term “Cold War” has made a rapid comeback. Even before the recent American election, USA Today spoke of, “A New Cold War?” and CNN ran as one of its headlines: “Cold War-style conflict.” This past week, the Toronto Star reported of apocalypse survival food kits being sold by Costco Canada. This country, which has historically been one of the key boosters of internationalism, is now looking on in mild alarm as nationalism not only flourishes south of the border and in key European states, but is subtly emerging in various Canadian contexts, including the Conservative leadership race.This country is finding itself impinged in the vice between nationalism and internationalism. Trump's bewildering sense of American identity represents just as much a challenge to Justin Trudeau as Vladimir Putin's rampant militarism. This isn't just about nuclear weapons, but cyber warfare and the flagrantly hostile actions of Russia over other nations. In such a context, peacekeeping and good intentions seem somehow underwhelming. As Robert Legvold, political scientist and Professor Emeritus at Columbia University, sees it, “we have entered a second Cold War, only perhaps more dangerous because of the unstable global environment and the more modern challenges of cyber warfare and terrorism.”The Cold War might be returning for another round of global freezing, but this time it's different. Where the United States and its partners made direct military interventions in places like Vietnam, Korea, even Bosnia, you'll see nothing similar in Crimea or the Ukraine, where Russia roams with menace. And as China brandishes its might in the South China Sea, we seem to have entered a period of great uncertainty where Canada, like other nations, must reassess the manner of its own engagement in such a turbulent world.With a fractured Western coalition and a surging populism on both sides of the Atlantic that is frequently isolationist in nature, Canada is seeking to walk a fine line between playing a global role for progress and keeping its own domestic house from fracturing. Of the two, the latter is more subtle and likely more dangerous.Former American diplomat George Kennan, who wrote much of the book on how to contain the old Soviet Union, threw out a warning that Canada, like every other nation, must abide by if the present world isn't to fall into a new era of threat and darkness: “The greatest danger that can befall us in coping with the problem of Soviet communism is that we shall allow ourselves to become like those with whom we are coping.”Communism isn't the greatest threat to peace in this new Cold War, nor is it Putin. Rather, it is the embedded nationalism that threatens to turn peaceful and tolerant nations into narrow and irreconcilable ones.Glen Pearson was a career professional firefighter and is a former Member of Parliament from southwestern Ontario.  He and his wife adopted three children from South Sudan and reside in London, Ontario.  He has been the co-director of the London Food Bank for 29 years.  He writes regularly for the London Free Press and also shares his views on a blog entitled “The Parallel Parliament“.   Follow him on twitter @GlenPearson.