Canada could be right back at the bargaining table with the United States, once again negotiating a new trade agreement after having barely just completed the last one .

If a Democrat wins the White House, it's a strong possibility.

Now that the race is down to two main contenders for the Democratic nomination, it's easier to do a side-by-side comparison of the potential policy outcomes for Canada.

One major implication involves trade policy, as Joe Biden and Bernie Sanders have both made clear they would like to negotiate new international commercial arrangements.

That's where the similarities end. Because the candidates have strikingly different views on international trade, and have different deals in mind.

Some issues of importance to Canada are obviously tough to predict — such as how a presidential hopeful would respond to a global crisis like coronavirus.

But on several issues of consequence to Canada, Sanders and Biden have made their views crystal clear.

"The good thing is all the candidates are familiar," said Chris Sands, head of the Canada Institute at Washington's Wilson Center.

"You'll see the issues coming."

Sands said that whoever wins this election, from whichever party, that person's policies will be better known to Canada than Donald Trump's in 2016, or even Barack Obama's in 2008.

Here's how the Democratic candidates' views on trade, energy, climate change, and military co-operation might affect Canada.

Trade: Biden

Biden's goal — make America a Trans-Pacific signatory again. The former vice-president has made clear he would seek U.S. participation in the deal formerly known as the Trans-Pacific Partnership (TPP), which was a centrepiece of the Obama trade agenda. After U.S. President Donald Trump cancelled the deal, Canada and 10 other countries joined on without the U.S., creating the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP).

In a Democratic debate last year, Biden was adamant: "I'd renegotiate," he said. Biden cast it as a matter of American leadership, in an effort to ensure that free-market countries, and not China, write the global trading rules of the 21st century.

Joe Biden on whether he would rejoin the Trans-Pacific Partnership trade deal: "I would not rejoin the TPP as it was initially put forward. I would insist that we renegotiate pieces of that." <a href="https://twitter.com/hashtag/DemDebate?src=hash&ref_src=twsrc%5Etfw">#DemDebate</a> <a href="https://t.co/gOJs7TRSVp">https://t.co/gOJs7TRSVp</a> <a href="https://t.co/5ooSBNIbOm">pic.twitter.com/5ooSBNIbOm</a> —@CNN

What would Biden seek in a revamped deal? He says he wants environmental and labour groups more involved in talks. Biden might also try getting U.S. farmers access to some of the dairy quotas in the current CPTPP, which could create friction.

Sarah Goldfeder, a former U.S. diplomat posted in Ottawa during the original TPP talks, says the dairy details would be a simple copy-and-paste from the update to NAFTA. A Biden presidency would also restore predictability to the World Trade Organization, said Goldfeder, who now works at Earnscliffe Strategy Group in Ottawa.

There would be one major long-term consequence for Canada if the U.S. re-enters the trans-Pacific pact. It would effectively cancel one of the most controversial aspects of the new NAFTA deal — the so-called sunset clause . Canadian officials spent months resisting the clause, which requires countries to start renegotiating the deal every few years, under threat of the agreement being cancelled in 16 years.

A new TPP would validate a strategy privately mapped out by some Canadian officials, who urged colleagues to just accept the sunset clause. Their rationale? The new NAFTA might only be a temporary deal, a brief stopgap to keep trade flowing through the Trump era. Should Biden enter the CPTPP , it would likely entrench a trading arrangement without a sunset clause.

Sanders adresses supporters at a rally in Columbia, South Carolina, on February 28. (Jim Watson/AFP via Getty Images)

Trade: Sanders

Sanders would not rejoin the TPP. In fact, Sanders celebrated its original demise at the hands of Trump. The deal Sanders wants to renegotiate? The new NAFTA, known in the U.S. as USMCA.

In a speech to the Senate, Sanders complained that USMCA doesn't mention climate change. Specifically, he lamented that it lowered trade barriers on the diluent products that help oilsands bitumen flow through pipelines.

"It makes it easier for fossil fuel companies to bring tar sands oil into the United States through dangerous pipelines like the Keystone XL," Sanders said.

Sanders wants the deal changed in other ways that would put him at odds with the Canadian government: he wants more scope for Buy American laws. Sanders has also frequently called for country-of-origin labelling , so that meat from foreign livestock would be labelled as such in grocery stores.

One U.S. trade expert who has discussed the USMCA with Sanders, said his opposition to the deal goes beyond his comments on climate change. Sanders also maintains the labour provisions are too weak to keep jobs in the U.S., the expert said.

Suncor's base plant with upgraders in the oil sands in Fort McMurray Alta, on Monday June 13, 2017. (Jason Franson/The Canadian Press)

Energy and the environment: Biden

When asked at a South Carolina rally what his top priorities would be as president, Biden said the Paris climate accord was top of his list. He vowed to rejoin it on Day 1 of his presidency.

Biden's climate plan would also push other countries to ramp up their Paris commitments. He would restore Obama-era co-operation with Canada on Arctic issues , by blocking Trump's move to allow oil and gas leasing in the Arctic. He also promises to work with Arctic Council members, like Canada, to extend that drilling moratorium globally.

Biden's platform also calls for a 100 per cent clean-energy economy and net-zero emissions by 2050. It would also seek to spend $1.7 trillion over 10 years on green technology.

Biden has criticized Canadian oil. When asked in a New York Times editorial board interview why he condemned Chinese pollution but not Canadian oil, Biden said he also opposed "what Canada's doing, in terms of the pipelines and the dirty crude they're sending south on us."

Biden was part of the Obama administration that originally blocked the Keystone XL pipeline. But his name is notably absent from the list of candidates who have vowed to reverse Trump's approval of the still-incomplete pipeline.

Canadian author and activist Naomi Klein, speaking at a Sanders campaign event in Las Vegas on Feb. 20, 2020, says his climate policies would not only move off fossil fuels faster, but would be politically smarter too. (Alexander Panetta/CBC News)

Energy and the environment: Sanders

Sanders is far more aggressive on the issue — blocking Keystone XL is just a start. Sanders does not want oil shipped; he wants oil executives punished. His Green New Deal plan calls for criminal and civil suits against oil executives for damage caused by climate change — inspired by the penalties against the tobacco industry.

Sanders wants to ban U.S. imports of oil, of which Canada currently ships more than 3.5 million barrels per day to the U.S. He'd also end new federal fossil fuel infrastructure permits and ban fracking.

To ease the transition to a green economy, he says he would guarantee five years of fossil fuel workers' current salary, housing assistance, and job training or pension payments.

Speaking at a campaign event before the Nevada caucuses, Canadian journalist and author Naomi Klein, a Sanders supporter, said — unlike other candidates — Sanders grasps the urgency of the climate situation.

"Bernie's the only one who actually recognizes that … we need to move faster." She said his across-the-board approach would not only yield more results — in her estimation, it would actually get more public support than more mainstream policies like carbon taxes and cap-and-trade systems.

In this Monday, May 27, 2019, photo, NATO forces attend the graduation ceremony of Afghan National Army soldiers from a training program in Kabul, Afghanistan. Biden and Sanders have quite different takes on U.S. military adventurism. (Rahmat Gul/The Associated Press)

NATO and defence: Biden

Biden calls NATO the most effective political-military alliance in modern history. He says he's troubled by growing authoritarianism around the world, and by democratic backsliding within NATO itself. Biden said he wants to bolster NATO members' commitment to democracy.

He even released a campaign ad featuring Prime Minister Justin Trudeau and other leaders at a NATO summit having a laugh when talking about Trump.

The world is laughing at President Trump. They see him for what he really is: dangerously incompetent and incapable of world leadership.<br><br>We cannot give him four more years as commander in chief. <a href="https://t.co/IR8K2k54YQ">pic.twitter.com/IR8K2k54YQ</a> —@JoeBiden

Biden has criticized Trump for constantly threatening allies, as he presses them to increase military spending. "NATO is not a protection racket," Biden said while campaigning in Iowa.

"Biden is a traditional NATO guy," Sands said. "He'll ease up a bit on the browbeating [of allies] over defence spending — but not by much."

Biden went to Ottawa and had a friendly meeting with Trudeau in December 2016, shortly before Trump took office. (Chris Wattie/Reuters)

NATO and defence: Sanders

Sanders is a frequent, decades-long critic of U.S. foreign military adventurism. Yet he shares some of Biden's views on the merits of the international alliance.

"I believe in NATO. I believe that the United States, everything being equal, should be working with other countries in alliance, not doing it alone," Sanders recently said on 60 Minutes.

Sanders has even said he would take military action under various circumstances — like protecting Americans, preventing Iran and North Korea from obtaining nuclear weapons, intervening in a humanitarian crisis, or protecting Taiwan from Chinese invasion.

Sanders has also made comments in the past illustrating that American frustration with other countries' military spending goes far beyond Trump, and his predecessor Obama , and spans the entire U.S. political spectrum.

In a 2016 debate, Sanders said he would "not be embarrassed" to tell allies that "you've got to put up your own fair share of the defence burden."

Even if Sanders rarely talks about military issues, Goldfeder said it's a safe bet any secretary of defence he appoints would keep up the pressure for allies to spend on defence.