Washington (CNN) The political tumult that rocked the world in 2016 might be an appetizer for 2017.

Crucial elections loom this year in France and Germany, where the same anti-establishment backlash that produced Donald Trump and Brexit could offer an opening to nationalist leaders who oppose Muslim immigration and further erode the European unity that has been a signature of the post-World War II era.

The Middle East is spiraling deeper into the mire of fraying borders and sectarian disorder while violence in places such Syria is unleashing a tide of desperate refugees that is destabilizing Europe. Meanwhile, rising powers such as China, Russia and Iran are closely watching the developments to determine whether the convulsions in the West give them an opening to advance their own interests.

Of course, the 15 years since the September 11 attacks have been dominated by war, strife and economic disruption. But what makes 2017 so unique is that America -- long a force for stability -- is poised to inaugurate one of the most impulsive presidents ever to walk into the Oval Office.

Far from acting as a brake against turmoil sweeping the globe, America under Trump could exacerbate it. Nicholas Dungan, an Atlantic Council senior fellow, said uncertainty about the President-elect could widen divides in the transatlantic alliance, the bedrock of 70 years of Western stability.

"Donald Trump is in many respects the anti-Barack Obama," said Dungan, who teaches at Sciences Po, an international research university in France. "With Obama, there was tremendous trust but very little performance. With Trump it looks like there will be a deficit of trust and a surfeit of action."

World on edge

It's no wonder that Trump has the world on edge, despite arguments among supporters that the unpredictable statesmanship he has previewed in the presidential transition could strengthen the US position around the globe by keeping rivals off balance.

He has questioned US alliances that kept the peace for decades in Europe and Asia and suggested he will "expand" the US nuclear arsenal. He has spent his transition feuding with spy agencies that concluded Russia interfered in the election. And he signaled to China that the taboo topic of Taiwan is on the table, casting doubt on 40 years of diplomatic protocol.

The Trump effect could be all the more pronounced because the political equilibrium of much of the world has been upset, straining institutions and assumptions in international relations that have endured for decades. To judge how much has changed, and why the prospects of 2017 look so uncertain, it's worth looking back a year.

When 2016 dawned, Obama, fresh from an Iran nuclear deal and seeing Obamacare upheld by the Supreme Court had every reason to expect a Democratic successor would secure his legacy. Republicans were confidently waiting for an establishment champion to emerge from their primary to send Trump back to reality TV.

In Britain, David Cameron was basking in a surprising parliamentary majority won in a 2015 election. Most end-of-year polls predicted the Remain camp would win a referendum on membership in the European Union.

In Germany, Chancellor Angela Merkel, Time Magazine's reigning Person of the Year, was lauded for her moral example in embracing desperate refugees from the Middle East and was Europe's undisputed leader.

And in Italy, Prime Minister Matteo Renzi was readying a trip to the US to receive Obama's blessing after harnessing hope and change as a successful political message of his own.

Unthinkable happened again and again and again

But within months, the unthinkable happened -- again, and again, and again.

In a blink of an eye, Cameron was gone, felled by a referendum in which voters who felt economically and culturally dispossessed opted to leave the EU.

Trump won the US election after a vitriolic campaign that tore at social, cultural and political divides and left the rest of the world confused about American power and identity.

Renzi is history, crushed Cameron-style by his own referendum defeat which dealt a second hammer blow to the EU.

And Merkel, rocked by a year-end terror attack in Berlin,faces a fight for political survival in a fall election hinging on immigration politics and a right wing resurgence spurred by her open door refugee policy.

In France, where Islamic terrorism has become more frequent, President Francois Hollande acknowledged his dismal approval rating and nixed a re-election bid. The best hedge against an earthquake election win in May by far right national front leader Marine Le Pen is France's two-round election system that could unite opposition against her.

A March election in the Netherlands promises a strong showing by far right leader Geert Wilders built on skepticism towards Brussels that is threatening the existence of the EU.

Still if Merkel or an establishment rival prevails in Germany, and the hot favorite in the polls to win the French presidency, Francois Fillon, is also victorious, 2017 could be remembered as the year the populist revolt began to ebb.

Adversaries mobilize

As the West reels, its adversaries are mobilizing.

Russian President Vladimir Putin defied Obama's predictions his venture in Syria would end in a quagmire. Now, he seems on the way to restoring the lost Russian influence that he watched ebb in despair after the fall of the Soviet Union.

In Asia, Chinese President Xi Jinping is accelerating that country's accumulation of regional power and challenging US influence and allies in the South China Sea. A volatile President in the Philippines, Rodrigo Duterte, is trashing a prized US alliance.

Trump's rejection of a vast Trans-Pacific Partnership trade pact has already empowered Chinaand undermined eight years of Obama's Asia pivot.

The instability and uncertainty makes the choices Trump makes once he is inaugurated in January especially crucial.

Should the new administration follow through on the President-elect's tough rhetoric on China and take protectionist steps that could incite a trade war, tensions in Asia could spike considerably.

If Trump walks out on the Iran nuclear deal or infringes the Paris climate pact, he could send transatlantic relations into a spiral. Aligning the US closer to Moscow could also alarm European allies unless he makes a full-throated defense of NATO on his first trip to the continent.

Asian allies Japan and South Korea are nervously trying to work out what Trump's campaign trail rhetoric means for crucial national security infrastructure in Asia. North Korea, meanwhile, is brewing what could be Trump's first big foreign crisis with its race for a functioning nuclear arsenal.

In the Middle East, Trump's vow to move the US embassy to Jerusalem from Tel Aviv could light a match to Palestinian-Israeli antagonism and put US Arab allies in a tough spot.

Could Trump's strategy work?

Of course, there's no certainty that Trump will plunge the world into a new spiral of instability. Major policy shifts can be disorienting, but they aren't always negative.

Every President's foreign policy is in some ways a correction to that of his predecessor. So Trump's spontaneity could perhaps be an antidote to Obama's caution, which some critics said frittered away US power.

Questioning trade deals, alliances and conventions could actually end up strengthening the US at home and in the world, Trump supporters argue. And just because the One China policy has dictated relations between Washington and Beijing for decades does not mean it should always be so, they say. Trump's naval buildup, meanwhile, could reassure US allies who feel bullied by China.

And in an era of strongman leaders like Xi, Putin and Turkish President Recep Tayyip Erdogan, a harder-to-read US President might keep American rivals off balance.

Foreign policy often begins at home. And if tax cuts and slashing regulation ignites explosive economic growth, a Trump boom could help lift anemic economies in Euorope and Asia.

Those who hope Trump will not upset the geopolitical apple cart also question whether responsibility will sober the President-elect.

"There's just a whole different attitude and vibe when you're not in power as when you're in power," Obama said in his year-end press conference. "What we have to see is how will the President-elect operate and how will his team operate when they've been fully briefed on all these issues, they have their hands on all the levers of government and they've got to got to start making decisions."