75 years after D-Day, has the old alliance fallen apart?

A disjointed and politically distracted collection of Allied nations, including Canada, gathered in Britain on Wednesday to kick off a series of commemorations marking the 75th anniversary of the June 6, 1944 D-Day landings.

The Queen and BritishPrime Minister Theresa May hostedrepresentatives from each nation that fought in Normandy for a ceremony in the Southsea Common area of Portsmouth, where the vast majority of British, Canadian and American troops departed for the invasion.

Prime Minister Justin Trudeau was there, as wasU.S. President Donald Trump, whose state visit to Britain this weektriggered massive protests and Twitter-storms of public outrage.

British media reported thatsome residents of Portsmouth, long known for their displays ofhospitality to returning veterans, planned to skip the ceremony partly to show their disapproval of the U.S. president and partly because ofthe extraordinary extent of security measures planned for the event,which include the erection ofa high steel fence around the site.

One of the online fights picked by Trump during his visit has been with the mayor of London, Sadiq Khan, who was described bythe U.S. president as a "stone cold loser."

Trudeau isslated to meet with Khan on Wednesday and later in the evening with Australian Prime Minister Scott Morrison.

With May about to step down as prime minister and Trudeau preoccupied with this fall's federal election, the gathering presents an interesting contrast to the steely image of unity in adversitythat D-Day is supposed to represent.

Even still, there was a remarkable display of pageantry Wednesday under a gun-metal grey sky as British warships fired a salute and a parade of air power including a Second World War Spifitre and Hurricane conducted a flypast.

The Queen spoke of the sacrifices of her generation and thanked the old soldiers who saluted her.

Each leader told their nation's story in different ways.

Trudeau, in his speech, paid tribute to Lt.-Col. Cecil Merritt, the formerparliamentarian who as commander of the South Saskatchewan Regiment in the disastrous Dieppe raid, hadwon the Victoria Cross.

Many historians credit the raid with teaching Allies valuable lessons ahead of D-Day.

Trump quoted from Franklin Roosevelt and French President Emmanuel Macron read from a letter belonging to a French resistance fighter.

Paired with swing music, interviews with surviving veterans and a recording of Winston Churchill's wartime speech, it was all deeply nostalgic and harkened back to a time when everyone marched and even perhaps danced to the same beat.

The invasion of Hitler's 'fortress Europe' was not merely an extraordinary feat of arms, logistics and military planning. It was also a remarkable political achievement one that has prompted historians and pundits over the decades to wonder whether it could ever be repeated.

To be sure, the allies were a rancorous lot in 1944,with Russian dictatorJoseph Stalin's distrust ofthe western democracies and U.S. President Franklin Roosevelt's disdain for France's Charles DeGaulle.

What united them were common enemies.

Glimmers of unity

Marc Milner, director of the Gregg Centre for the Study of War at the University of New Brunswick, said we've seen flashes of that kind of unity during the interceding decades, notably in the first Gulf War against Iraq's Saddam Hussein.

"So yes, I suspect we could do something similar to D-Day again," said Milner, offering the caveat that nations would have to be properlygalvanized into action.

What we likely won't see again, he said,is anothertotal industrial war.

"The likelihood of an all-out and prolonged conventional war with mass mobilization of people and industry is, however, unlikely in the nuclear age," Milner said.

"In modern total war, our role is largely passive. We can stay at home and watch the missiles coming in on our TVs."

NATO as a political football

When the Allies planned D-Day, they had to invent and negotiate many of the structures and procedures necessary to carry out the invasion.

That kind of co-operation still exists in the "well-developed military structure" that is NATO, said Walter Dorn, a professor of defence studies at the Royal Military College of Canada.

It's an institution that allies can plug into for major deployments and would make it easier today to politically organize a major multinational campaign.

But since the end of the Cold War, NATO has expanded to include 29 members with disparate interests. Many NATO partnerssquabbleover both the alliance'sdecision-making process and the cost of maintaining the military alliance.

Trump has openly mused about pulling the U.S. out of NATO unless Allies continue to increase their defence spending, demanding that more of them meet the two per cent of GDPtarget that has become the alliance's benchmark.

Political paralysis

Dorn said political paralysis in domestic decision-making would make another D-Day difficult to stage these days.

He pointed to the unfulfilled peacekeeping promises made to the United Nations by the current Liberal government.

"The painfully slow progress of Canada to live up to its UN commitments in peacekeeping does make me wonder how fast the Canadian government could mobilize to meet other commitments, particularly ones involving high risk," he said

"The Trudeau government has avoided risky commitments in peacekeeping and has left the heavy lifting to others.So in the case of a major outbreak of conflict, one would have to wonder how quick and dependable Canada would be."

Still, Canada proved to be a stalwart ally in Afghanistan and has taken leadership positions in both NATO's Iraq training mission and the Baltics, commanding a battle group there intended to deter Russian aggression.

Although both missions are risky, they represent safe political choices at a time when western democracies are unwilling to tolerate the casualties associated with modern conflicts.

Andthat perhaps more than political and trade differences would make another D-Day an unlikely proposition.