On June 28, 1914, a chauffeur panicked after a failed bomb attack on his boss, took a wrong turn and came to a complete stop in front of a café in Sarajevo where Gavrilo Princip was sitting. Princip, discouraged at the apparent failure of the planned murder, seized the unexpected opportunity and fired the shots that began the First World War, a cataclysm which claimed over nine million lives, ended four empires and set in motion events from the Communist Revolution in Russia to the rise of Nazi Germany.

One hundred years later, the world is nervously keeping its eyes peeled for misguided chauffeurs and asking itself whether history could repeat. The great powers are at peace, and trade and cultural ties between nations seem closer than ever before, yet the international scene is in many ways surprisingly brittle. In particular, a rising naval power is challenging an established hegemon, and a "powder keg" region replete with ethnic and religious quarrels looks less stable by the day.

In 1914, Germany was the rising power, the U.K. the weary hegemon and the Balkans was the powder keg. In 2014, China is rising, the United States is staggering under the burden of world leadership and the Middle East is the powder keg.

Only a few years ago, most western observers believed that the age of geopolitical rivalry and great power war was over. Today, with Russian forces in Ukraine, religious wars exploding across the Middle East, and territorial disputes leading to one crisis after another in the East and South China seas, the outlook is darker. Serious people now ask whether we have moved from a post-war into a pre-war world. Could some incident somewhere in the world spark another global war?

MIDDLE EAST POWDER KEG

Let's start with the powder keg. The immediate cause of the fighting in World War I was the set of ethnic and religious conflicts in the Balkans. In the second half of the 19th century, economic development and modernization led to heightened competition among the region's peoples. The drive for self-determination set Croats, Serbs, Magyars, Kosovars, Bosniaks, Macedonians, Bulgarians, Greeks and others at one another's throats. The death toll mounted and the hatred grew as massacres and ethnic cleansing spread -- and the ability of the outside powers to control the region's dynamics shrank as the imperial powers were themselves undermined by rising social and nationalist tensions.

The Middle East today bears an ominous resemblance to the Balkans of that period. The contemporary Middle East has an unstable blend of ethnicities and religions uneasily coexisting within boundaries arbitrarily marked off by external empires. Ninety-five years after the French and the British first parceled out the lands of the fallen Ottoman caliphate, that arrangement is now coming to an end. Events in Iraq and Syria suggest that the Middle East could be in for carnage and upheaval as great as anything the Balkans saw. The great powers are losing the ability to hold their clients in check; the Middle East today is at least as explosive as the Balkan region was a century ago.

GERMANS THEN, CHINESE NOW

What blew the Archduke's murder up into a catastrophic world war, though, was not the tribal struggle in southeastern Europe. It took the hegemonic ambitions of the German Empire to turn a local conflict into a universal conflagration. Having eclipsed France as the dominant military power in Europe, Germany aimed to surpass Britain on the seas and to recast the emerging world order along lines that better suited it. Yet the rising power was also insecure, fearing that worried neighbors would gang up against it. In the crisis in the Balkans, Germany both felt a need to back its weak ally Austria and saw a chance to deal with its opponents on favorable terms.

Could something like that happen again? China today is both rising and turning to the sea in ways that Kaiser Wilhelm would understand. Like Germany in 1914, China has emerged in the last 30 years as a major economic power, and it has chosen to invest a growing share of its growing wealth in military spending.

But here the analogy begins to get complicated and even breaks down a bit. Neither China nor any Chinese ally is competing directly with the United States and its allies in the Middle East. China isn't (yet) taking a side in the Sunni-Shia dispute, and all it really wants in the Middle East is quiet; China wants that oil to flow as peacefully and cheaply as possible.

AMERICA HAS ALL THE ALLIES And there's another difference: alliance systems. The Great Powers of 1914 were divided into two roughly equal military blocs: Austria, Germany, Italy and potentially the Ottoman Empire confronted Russia, France and potentially Britain.

"Today the global U.S. alliance system has no rival or peer; while China, Russia and a handful of lesser powers are disengaged from, and in some cases even hostile to, the U.S. system, the military balance isn't even close."

Today the global U.S. alliance system has no rival or peer; while China, Russia and a handful of lesser powers are disengaged from, and in some cases even hostile to, the U.S. system, the military balance isn't even close.

While crises between China and U.S. allies on its periphery like the Philippines could escalate into US-China crises, we don't have anything comparable to the complex and finely balanced international system at the time of World War I. Austria-Hungary attacked Serbia and as a direct result of that Germany attacked Belgium. It's hard to see how, for example, a Turkish attack on Syria could cause China to attack Vietnam. Today's crises are simpler, more direct and more easily controlled by the top powers.

On the other hand, the Middle East's supplies of oil will keep China, as well as other powers, more involved in events there than geography would suggest. The Balkans had no products in 1914 that the rest of the world much cared about; the Middle East looms much larger in the global economy than the Balkan peninsula ever has. Already, countries including Russia and Iran have been involving themselves in Iraq. If the slide into regional chaos continues and countries like China and Japan believe that direct action is needed to secure their oil supplies, almost anything could happen in a few years.

ASIA IN 2014 IS NOT EUROPE IN 1914 Furthermore, the geopolitical situation of Xi's China is more different from that of Wilhelm's Germany than many observers realize. While it is true that many of the same forces that drove Germany toward war 100 years ago are present in China today (especially a public mood of nationalism and an aggressive military psychology among some of the armed forces leadership), there are differences as well.

In 1914, Germany was a rising empire surrounded by powers who were, and who felt themselves to be, in decline: Russia, Austria-Hungary, Britain, the Ottoman Empire and France all felt themselves to be in decline. China's neighbors today are growing China militarily and economically: South Korea, Australia, India, and the nations of South-East Asia. Germany's growing preponderance in Europe was tipping the balance of power toward instability. It's not yet clear that something like that will or can happen in Asia.

Besides the Germany/China parallel, there is the question of whether the U.S. today is beginning to resemble Great Britain. In 1914, Britain was the only global superpower in the sense that nobody had an empire as large, played as important a role in managing the world financial system, or provided the same kind of political and military security to the international system, but many in Britain were beginning to think that its best days were behind it.

By 1914, both the U.S. and Germany had passed Britain in economic terms, and internal political paralysis was turning the country inward. (The political struggles that would result in the partition of Ireland had much of the British army in a state approaching mutiny in the months before Sarajevo.)

A small but significant number of historians blame Great Britain, as well as Germany, for the outbreak of that conflict. France was the bitterest and most committed of Germany's enemies, but Germany (then Prussia) had beaten her soundly in the Franco-Prussian War one generation previously. France's ally Russia was a formidable power on paper, but the Japanese had savaged the Russians in the past decade, and a wave of revolutionary agitation nearly brought the Tsarist system to its knees.

Germany didn't think a war against those two powers would be a cakewalk, but Wilhelm and many of his advisors thought that Britain would stay out of any war over Serbia. The Kaiser, some argue, would probably have thought twice had he known that he would be fighting the full weight of Britain and her Empire. If the British had made clear to the Germans that they would stand by Russia and France, it is possible that German diplomacy in the fateful month of July 1914 would have reined in Austria-Hungary rather than egging it on.

AMERICA IN 2014 IS NOT QUITE BRITAIN IN 1914 Despite worries about the rise of China, the place of the United States at the pinnacle of world power is more secure today than Britain's was 100 years ago. The U.S. economy is a larger share of GDP, the U.S. military advantage is qualitatively greater than anything Britain ever enjoyed, and none of its political problems are as polarizing as the Irish question or the rise of a socialist working class party were for the U.K. in 1914.

Even so, it is possible that other powers may not be sure how committed the United States is to defending its allies or its interests around the world, and that can make bold or even rash moves look attractive.

It's possible, for example, that some people in the Chinese leadership look at President Obama's mixed messages about his "red lines" in Syria and wonder how seriously to take American red lines in the Pacific. Would the U.S. really go to war over a handful of uninhabited rocks scattered through the East and South China seas? Would we take stronger steps against an invasion of Taiwan than we have against Russia's conquest of the Crimea? Russia and Iran may be asking themselves similar questions and looking for places where they can push against what they see as weak spots in the U.S. alliance system. At the same time, countries that depend on U.S. guarantees (like Israel and Japan) may become more aggressive to deter potential adversaries.

RAILROADS THEN, DIGITAL NETWORKS AND DRONES NOW There was one more factor that contributed to the outbreak of World War I: technological change introduced new factors into warfare that policymakers failed to understand. A driving force in the tragedy of 1914 was the impact that mobilization timetables had on diplomatic and military choices.

The development of national railroad networks in the 19th century allowed countries to call up reserves and mobilize their forces for war on an unprecedented scale. On the other hand, once your neighbor began to mobilize, you had to move yourself; otherwise, your armies would still be scattered while your neighbor had a large and powerful force on the frontier. Russia had the largest armies, but the size of its territory and the relatively backward state of its railroad network meant that it had to mobilize early in a crisis or risk being caught unprepared. But once Russia began to mobilize, Germany could not delay its own move much longer, and German mobilization forced France's hand. Few European policymakers on the day of Franz Ferdinand's death understood how railroad timetables would force their hands in the weeks ahead.

"'Few European policymakers on the day of Franz Ferdinand's death understood how railroad timetables would force their hands in the weeks ahead."

Today the disruptive effect of technological change is greater than ever. New weapons systems emerge (like drones) that transform the balance of power and set off new and unpredictable arms races. As information technology transforms the battlefield, tech itself becomes a battleground in a new era in war. Disrupting the enemy's communications, attacking its information systems (through viruses, attacks on communications satellites and EMPs for example) and otherwise wreaking havoc in cyberspace is a new frontier in war which nobody really understands.

The rapid pace of technological change makes it harder for policymakers to assess the strength of their opponents even as it puts them under pressure to speed their deliberations in a time of crisis. No one wants to be the victim of a cyberspace version of Pearl Harbor, so leaders may feel forced to accelerate the move toward war before suffering a devastating attack.

Technological change had another, deeper role in the making of World War I. The unprecedented social shifts that accompanied the Industrial Revolution had a lot to do with the shifts in the balance of power and the rise of ideologies like nationalism and socialism that made the period so turbulent. We are certainly seeing that again today; globalization put societies all over the world under stress, and that stress often results in the rise of nationalist and even chauvinist political movements in some countries and religious fanaticism in others.

DON'T FORGET ABOUT NUCLEAR WEAPONS One more factor needs to be noted. The existence of nuclear weapons has changed the terms on which great powers engage. In 1914, nations could still hurl everything they had at one another in a struggle to the death; nuclear weapons change that dynamic. No major war can be as politically straightforward as war traditionally has been; the prospect of nuclear escalation will inhibit both sides in future crises as it did the U.S. and the USSR during the Cold War.

NOT THE SAME, BUT ALSO NOT SO DIFFERENT History, perhaps unfortunately, can't give us a clear answer to the question of whether we face anything like another Great War. Looking into the rear view mirror can only tell you so much about the conditions ahead. Our situation today is different enough from that of a century ago to make renewed great power war much less than a certainty, but there are enough troubling similarities that we can't rule the prospect out.

The one thing we can say with certainty about the 21st century is this: peaceful or war-torn, it isn't going to be boring.