A decades-old lament for Canada is back on some Canadians' minds as United States President Donald Trump makes repeated annexation threats.

Canadian political philosopher George Grant's Lament for a Nation was published in 1965 - the same year Canada's iconic Maple Leaf flag was first unfurled on the Peace Tower on Parliament Hill - and unexpectedly inspired many Canadians to feel a sudden sense of pride and confidence that their country could and must stand up to its giant imperialistic neighbour to the south.

Sixty years later, there are calls to "Bring Back Grumpy George" and renew his decades-old warning. There are also attempts to understand Grant's continued relevance in the 21st century, as well as new volumes on his work.

On the face of it, Grant's slim volume may seem the perfect tonic for what ails Canada today. Consider that William Christian, Grant's biographer, called its publication "one of the most significant factors in creating the Canadian nationalist movement of the 1970s" while esteemed journalist Charles P.B. Taylor dubbed it "a Bible for younger nationalists."

It "is the sun under which a generation of Canadian nationalists warm themselves," Andrew Potter writes in his introduction to the 40th anniversary edition of Grant's most famous work, "but it also casts the long dark shadows in which they must operate."

One need only wade a little into the volume to see those "the long dark shadows." The subtitle to Grant's book says it all: The Defeat of Canadian Nationalism. So, far from being a call to arms, Lament for a Nation was, as Grant put it, a "cry out at the death or at the dying of something loved...[to mourn] the end of Canada as a sovereign state."

In other words, Lament was never intended to whip Canadians into a nationalist fervour, but to spell out Canada's unfortunate and inevitable disappearance as a nation.

By this logic, the next six decades of failed strategies to diversify the Canadian economy and stillborn plans to grow its military are symptoms of a disease that had already killed the patient; Canada is the zombie nation, an apparently democratic electoral system without real substance. Grant wrote:

"Canada has ceased to be a nation, but its formal political existence will not end quickly. Our social and economic blending into the empire will continue apace, but political union will probably be delayed. Some international catastrophe or great shift of power might speed up this process."

For Grant, Canada's original death knell was acquiescence to American demands that it accept their nuclear weapons on its soil. While Canada had both the technical ability and practical capacity to build its own bombs after the Second World War, leaders decided against it.

Jack Mackenzie, first president of Atomic Energy Control Board, explained in a 1953 address: "Canada is the only country in the world with sizeable atomic energy establishments where no bombs are being made, and where all the thinking and planning is focused on peacetime aspects."

But in the context of the Cold War, this principled choice was viewed as a sign of weakness by Americans, who worried about Soviet bombers travelling unrestricted over the Arctic.

This worry led to the so-called defence crisis that dominated the federal 1963 election campaign, fought between Conservative Prime Minister Diefenbaker and Liberal Lester B. Pearson.

A beleaguered Diefenbaker had cancelled the vaunted Avro Arrow program a few years earlier, hesitated to commit the Navy to participate in the blockade of Cuba and then balked at accepting American warheads for the BOMARC interceptor missiles designed to stop those bombers.

The pugnacious Pearson was once a champion of non-proliferation and had shocked his supporters during his infamous Scarborough speech when he announced his surprising agreement that U.S. nukes had to be deployed on Canadian soil in the name of our "commitments for Canada in continental and collective defence," including NORAD and NATO.

For Grant, Diefenbaker's defeat to Pearson was a stake through the heart of the Canada from which it would never recover. In 1963, the Royal Canadian Air Force delivered a shipment of nuclear warheads to the BOMARC missile site near RCAF Station North Bay, Ont., just up the road from where I write today.

A few years before his passing in 1988, Grant made it clear in a 1985 interview with Lawrence (Larry) Schmidt, a theologian and a scholar of Grant's work, that "people have read a little book I wrote called Lament for a Nation wrongly. I was talking about the end of Canadian nationalism. I was saying that this is over and people read it as if I was making an appeal for Canadian nationalism. I think that is just nonsense. I think they just read it wrongly."

Today, Canadian economic well-being and security are no more in Canada's control then they were in 1965. Trump is merely saying the quiet part out loud in his craven desire to make Canada the 51st state.

But, as it turns out, Grant was wrong. Canada is not the zombie nation. It may have been in a bit of daze for the last while, but Canadians have their elbows up again.

Read more: Why Gordie Howe's elbows are Canada's answer to Donald Trump

Now out of a stupor, Canadians are reviewing the wisdom of purchasing F-35s, buying new radar systems to assert our sovereignty over the Arctic and attempting to drop interprovincial trade barriers.

Mind you, this is nothing new. In the face of American disapproval, Canada trades with Cuba, claims the Northwest Passage as its internal waters and negotiated a successful Acid Rain Treaty. Canada led the charge to ban the use of land mines and refused to participate in the American missile shield plan.

Canada didn't send its young men to die in the jungles of Vietnam and refused to participate in the ill-conceived Iraq War. And it still protects its fresh water and health care.

Still, rather than merely reacting to American insults and pressures, Canada is long overdue to develop contemporary and responsive policy, the very thing Grant thought would allow Canada to become and stay a sovereign country, at least for a while.

As writer and historical researcher Mark Wegierski notes, this could unite conservatives and progressives in common cause.

While Canadians may be divided at times, they need to use this moment of unity to make sure Canada stays alive and kicking.