In 2008, as the Bush Administration drew to a close, there was a general sense among millennials that America was finally coming home.

We were returning home from war in Iraq, where more than 4,000 American troops perished at the hands of violent insurgents; home from an alliance with Pakistan, where autocrat Pervez Musharraf funneled U.S. aid to our enemy the Taliban; and home from confronting Russia, where President Medvedev’s recognition of South Ossetia and Abkhazia had caused tensions to rise to a post-Cold War high.

This sense of homecoming connoted an end to America’s unilateralist experiment. We would now return from largely going it alone in distant lands to working through our allies and shared institutions to maintain world order.

“We’re not going to be able to be everywhere all the time,” then Sen. Barack Obama said in a presidential debate against Sen. John McCain. “That’s why it’s so important for us to be able to work in concert with our allies.”

For some, this seemingly reasonable call for multilateralism reflected a tired desire to return home from the world, and return we did. Within six months of President Obama’s inauguration, troops began to return home from Iraq. Instead of the 16,000 to 24,000 residual forces that military commanders advocated, the White House sought 10,000, then 5,000, then complete withdrawal as negotiations failed with Al-Maliki.

Our forces in Afghanistan would begin to return home within two years, despite an initial surge. Troop levels are now as low as they have been since the Bush Administration. By 2015, 9,800 military personnel will remain of the 100,000 once stationed at the peak of the surge.

For some, homecoming meant that the America could “lead from behind.” In the previous decade, America had largely led the charge into the Middle East. Under the global order enforced by George H.W. Bush and Brent Scowcrof, it was the United States that led the coalition against Saddam Hussein to save Kuwait. Twenty years later in Libya, it was France and Britain’s turn to go first. Polls show that our generation, sick of unilateralism and hesitant to use overwhelming force, embraced this new multilateralist paradigm.

No matter what the sense of homecoming really meant in 2008, the world quickly changed, as it often does. Red lines blurred as the Obama administration declined to strike Bashar Al-Assad for using chemical weapons in Syria. A well-intentioned reset became a trite repeat as Vladimir Putin’s Russia annexed Crimea. A black sea of jihadists uprooted two nations and murdered thousands on its violent quest for a global caliphate.

Where a welcoming world once applauded us in Cairo, a dangerous state of anarchy now looms around the corner. Today, our generation watches as our president takes us back into Iraq and Syria, and it is our generation that will both fight and pay for these coming expeditions into foreign land.

The question is, do we have the resolve to do what must be done?

Surely, something must be done when a foreign army threatens genocide against besieged minorities — Yazidis, Turkmen, Christians — and we have the power to stop it. Likewise, we must act when this same military force existentially threatens our alliances with Jordan and Saudi Arabia, regional bastions against terrorism. As the lid comes off the Iraq that America remade, it is America that must once again make that lid and seal it.

Meanwhile, an ambitious Iran hopes that our common cause against ISIS will weaken our independent will. As we become entangled in an unlikely alliance against ISIS, Tehran will seek to leverage its position to weaken our limits of its nuclear program. If we fail to act on Iran, the result may be a regional arms race, increased terrorism and a weakening of the U.S. umbrella deterrent in the region and around the world.

Our generation will have to gain new resolve to deal with the threat that an Iranian nuclear arsenal poses, as we are notably soft on the issue. Only 44 percent of those younger than 30 favor taking a strong stand against Iran, while overwhelming majorities of our elders support a firm stance. With nuclear negotiations ongoing with the Iranians, this may seem moot to some. But if negotiations fail, it is vital that our generation, tired from the last decade of conflict, finds the will to act.

That our generation must act does not mean that we must sacrifice our values. Our infatuation with multilateralism does not preclude us from taking decisive action. The need to maintain the liberal world order that America has erected does not prevent us from working with allies. History has shown us, on the contrary, that those two goals are often inseparable. As impossible as it seems, Kissinger’s advocacy of a global balance and Robert Kagan’s American activism are not indefinitely irreconcilable.

But there will come a time when our allies are unwilling to act and we must once again walk down the lonely path of unilateralism. When that time comes we must first challenge the premises of action, but if satisfied, champion our actions abroad. Millennials cannot let our newfound stance on foreign policy be an excuse for inaction in a world that demands order. The stakes of inaction are just too high.

Our generation’s challenge, then, is finding, defining and hardening our will. This cannot happen overnight, especially with the bloody wars of Afghanistan and Iraq fresh in our young but potent memory. But it must happen.

Aaron Zelinger, a junior studying symbolic systems, is the international editor of Stanford Political Journal.