Our war in Afghanistan, which started in October 2001, will soon be older than our youngest soldiers. Endless, unwinnable Middle East conflicts have left Americans frustrated and impatient. Candidate Trump vowed to keep us out of these wars but has not withdrawn U.S. forces. Indeed, if we’re going to have a showdown with Iran, we’ll need more.

Trump has stumbled into Washington’s inability to define what kind of a world we face. I face it too, in the upcoming eleventh edition of my intro international relations textbook. I begin “IR: The New World of International Relations” with a review of past “world systems” and ask what is the current system, which is now dangerously unclear and shifting.

Yes, it’s a theoretical question, but it’s practical theory. Mistaking one system for another can produce catastrophes. The game we play in one system becomes unplayable in the next, as if an American football team had to play soccer. No one has accurately defined the current messy system.

Richard Haass’s term “disarray” fits, but he, advocating the U.S. play global “sheriff,” marched with the neo-cons into Iraq. Cold Warriors are uncomfortable with disorder and demand a cure for it. Disarray, however, may be the new normal, something we have to learn to cope with.

Prevailing wisdom that the Cold War bipolar system fragmented into a multipolar system is so general as to be worthless for much strategic planning. Yes, the U.S., Europe, Russia, China and Japan are sort of economic “poles,” but they are wildly unequal in terms of power, especially military power. Multipolarity also suggests that, unlike bipolarity, any one pole will have great difficulty leading others. President Trump seems intent on proving this.

In 1993, Harvard’s Samuel Huntington saw the new global system as a “clash of civilizations” in which several main cultural areas, based on their founding religions, emerged after the Cold War to variously get along and fight with each other. Biggest problem, he argued, was Islam. “Islam has bloody borders,” he wrote, later adding, “and bloody innards too.”

Although controversial, Huntington explains the current wave of terrorism — 9/11, Afghanistan, Iraq, Boko Haram and ISIS. Trump’s campaign claim that “Islam hates us” echoes this theme. Huntington’s problem is that all these civilizational areas are internally fragmented and lack solidarity. Trump is best buddies with Saudi Arabia but scorns Europe.

Globalization, which until recently some celebrated as the reigning system, may be starting to dissolve. It sees global corporations and markets marching us to prosperity. Capital flows to wherever it produces the best returns. This win-win game is supposed to promote liberal democracy and peace. High tech binds the world together, argued its prophet, New York Times columnist Thomas Friedman.

But after a few years of global growth, it becomes apparent that not all countries play fair; some become export maniacs, practicing neo-mercantilism and accumulating foreign reserves to no good end. Inequality explodes. Populists lash out against globalism and are willing to scuttle multilateral trade pacts, such as NAFTA, the TPP and even the WTO.

Globalization does not automatically lead to democracy, as China illustrates. The social media spew hate-filled messages and bomb-making instructions. Some early pioneers of social media envisioned a new, free world but now say that pursuing unlimited money through selling ads and data has perverted the entire project.

So, what kind of a world do we live in, and how do we cope with it? First, we must realize that we are no longer such a great economic power, a trend under way long before Trump accelerated it. World War II left the U.S. with the biggest economy, but growth in Europe and Asia has sharply reduced that gap.

Domestically, the U.S. has polarized into two hostile camps, making American leadership difficult to impossible. What internationalists favor as trade and security with partners, America Firsters see as giveaways to feckless freeloaders. America cannot define its national interests.

Looming across the Pacific, expansionist China’s $1-trillion Belt and Road Initiative (BRI) makes China the hub of Eurasia. But Beijing’s prideful ambition may have exceeded economic feasibility, and China is pulling back from money-losing overseas overinvestments. Some worry about a possible China-U.S. “rear-end collision” — a rising power overtakes the previously dominant power, as Germany collided with Britain around 1900.

Globally, nationalistic fragmentation and populist rage in Europe and the U.S. work against cooperation. The European Union weakens and could fall apart. Trump sees no danger in pulling out of the multilateral alliances and trading agreements that built postwar stability and prosperity. He lumps NATO together with NAFTA and could do without both.

Perhaps “power vacuum” describes the emerging global system, which resembles the interwar chaos and mistrust. Two large authoritarian powers are revisionist, aiming to tilt power in their favor. The democracies are passive while authoritarians expand into the vacuum: Ukraine, Syria, China Seas. No one stops them; no one leads.