In August 1941, Winston Churchill and Franklin Roosevelt met off the coast of Newfoundland to outline a shared vision for the post-World War II era. The British prime minister was so thrilled to see the American president that, in the words of one official, “You’d have thought he was being carried up into the heavens to meet God.” The two countries issued the Atlantic Charter, which sought “a better future for the world” through the principles of self-determination, collective security, and free trade. The United States hadn’t even entered the war yet, but it was already focused on winning the peace. The endgame was not just the defeat of the Axis powers, but also the creation of a stable global order, in which World War II would be the last world war.

Today, the United States is contemplating a major expansion of its military campaign against ISIS. Driven partly by faith that the end times are imminent, ISIS has stepped up expeditionary attacks outside its caliphate, including the bombing of a Russian jet over Egypt, a suicide attack in Lebanon, and coordinated assaults in Paris.

In the struggle against ISIS, however, far from preparing for the postwar world, U.S. politicians haven’t shown much interest in long-term thinking. Instead, the debate is fixated on immediate tactical questions, or which hill to capture. Who is planning for a better peace?

The Obama administration has neglected the endgame. In theory, the U.S. plan is to “degrade and destroy” ISIS through air strikes and aid to local troops on the ground. But the White House hasn’t mapped out what the path to strategic success might look like, or even the desired end state. Instead, to a large degree, President Obama has been improvising. Last spring, former Defense Secretary Robert Gates concluded: “We’re basically sort of playing this day to day.” After the Paris attacks, former Secretary of State Hillary Clinton offered a veiled critique of the president: “It’s time to begin a new phase and intensify and broaden our efforts to smash the would-be caliphate.”

Officials in the White House seem to fear that too much long-range planning could land the United States in yet another quagmire. If the administration publicly outlined a credible plan to defeat ISIS, it might commit the U.S. to a far greater investment of resources than is currently allocated. Obama himself appears to be deeply ambivalent about the goal of destroying ISIS. Chastened by the Iraq War, the president is particularly wary of being drawn into a costly campaign with uncertain odds of success. Instead, he emphasizes restricting the growth of ISIS. Just before the Paris attacks, Obama told ABC News, “From the start our goal has been first to contain, and we have contained them.” The logic seems to be: focus on the here and now, avoid sweeping plans, stay nimble, and look for new opportunities. It’s precisely because Obama sees ISIS as a long-term problem with no easy solution that he doesn’t want to think too far ahead. Keep the endgame murky and the options open—and expect to hand the problem over to the next guy.

Republicans, meanwhile, have also downplayed the endgame. GOP presidential candidates are fixated on the immediate step of hammering ISIS, rather than the ultimate goal of creating a durable order in the Middle East. Jeb Bush has suggested that the United States declare war on ISIS, set up no-fly zones and safe zones in Syria, and embed U.S. troops within the Iraqi military. He has also argued for the United States to battle Syrian President Bashar al-Assad’s regime: “We need to build a coalition that can fight both Assad and ISIS and give people safe haven.” Lindsey Graham has called for sending 10,000 U.S. ground troops to Iraq and Syria. Ted Cruz has pressed for more air strikes and for rushing equipment to the Kurds, “our boots on the ground.” Donald Trump has declared: “Bomb the shit outta them.”

These hawks may be neglecting the endgame because they fear that long-term thinking will deter the United States from escalating the campaign against ISIS. They are eager to obliterate the Islamic State, and they don’t want to be distracted by tough questions about, say, how Syria can be reconstructed from the ruins of war. Look too hard before we leap, and we might decide not to jump at all.

Improvisation might seem like a smart idea given the vagaries of war. After all, you can’t script a military campaign. Conflicts are complex and fluid, especially against a metamorphosing enemy like the terrorist-insurgent-state that is ISIS. It’s tough to predict events next week, never mind next year. But thinking through the endgame is a critical part of any wartime strategy. The Prussian military theorist Carl von Clausewitz advised against taking the first step in war “without considering the last.” And former U.S. Secretary of State Henry Kissinger wrote, “The test of policy is how it ends, not how it begins.”

A short-term mentality can be catastrophic during war. In the fall of 1941, as Churchill and FDR sketched the postwar global architecture, Japanese officials debated whether to launch a surprise attack against the United States. Rather than consider what a prolonged campaign versus the most powerful country in the world might look like, Japanese Prime Minister Hideki Tojo urged a leap of faith. “There are times when we must have the courage to do extraordinary things—like jumping, with eyes closed, off the veranda of the Kiyomizu Temple,” he said, in reference to a Buddhist shrine in Kyoto that juts out over a steep cliff edge. Four years later, every major Japanese city had been reduced to ashes.

Similarly, in 2003, the United States invaded Iraq with little heed to the long-term consequences. The George W. Bush administration was focused on the proximate goal of toppling Saddam Hussein, and largely ignored the question of how to stabilize Iraq afterwards. Tommy Franks, the head of U.S. Central Command, captured this mentality by telling the deputy secretary of defense: “You pay attention to the day after, I’ll pay attention to the day of.” But none of the key players paid enough attention to the day after. There was no plan to win the peace, and U.S. soldiers were left to improvise desperately as Iraq collapsed.

What is the endgame in the war against ISIS?

First of all, suppressing or defeating ISIS is not the goal. Rather, the aim is to create a secure Iraq and Syria. War is not about destroying the enemy; it’s about building a better peace so that the threat doesn’t reemerge. There’s no point in toppling a regime if the result is chaos and anarchy, whether that regime is the Taliban in Kabul, Saddam in Baghdad, Qaddafi in Tripoli—or ISIS in Raqqa. You can’t march away from smoking ruins and call it a victory. After all, ISIS’s predecessor was seriously weakened during the U.S. troop surge in Iraq in 2007. But the insurgents made a comeback due to sectarianism and misrule in Baghdad.

Who, for example, will govern the territory captured from ISIS? You break the caliphate, you own the caliphate. Stabilizing Syria and Iraq is a truly daunting task. It may require a decade-long humanitarian and peacekeeping effort. The United States will need to play a key role in this endeavor, which will very likely involve a commitment of American ground troops. If ISIS is pushed out of key cities, the insurgents won’t sign surrender documents like Japan did in 1945. Instead, they’ll wage a brutal campaign of terrorism to reclaim the caliphate. Are those fighting ISIS prepared for a wave of suicide bombings, kidnappings, and torture? Is the international community ready to invest billions of dollars in humanitarian aid and economic development? How will the U.S. and its allies win over Sunni Muslims to their cause rather than ISIS’s?

It’s tempting to leave tough questions like these for later, by winning the war first, and then—and only then—dealing with the stabilization phase. But the United States tried this approach before and it failed. Back in March 2003, Donald Rumsfeld, the secretary of defense, told Jay Garner, who was in charge of postwar reconstruction in Iraq: “I haven’t given you the time I should have given you. Quite frankly, I just have been so engulfed in the war that I just didn’t have time to focus on everything that you’re doing.” Rumsfeld saw the stabilization of Iraq as separate from, and secondary to, “the war”—when this goal should have been the whole focus of the military plan. Similarly, Jeb Bush recently suggested that the United States achieve a “total victory” over ISIS, “and then you need to forge political consensus to create a stable Syria and a stable Iraq.” Notice the “and then.” Shoot first, then worry about politics.

It’s also critical to consider the long-term consequences of today’s moves. Actions like inserting U.S. special forces into Syria or arming the Kurdish minority in Syria and Iraq create ripple effects that will alter the president’s room for maneuver in the months and years to come. A special-forces operative could be captured by insurgents, leading to a risky rescue mission or a politically costly prisoner exchange. Arming the Kurds today could help lay the groundwork for a Kurdish state tomorrow. On Tuesday, the potential for unintended consequences was vividly illustrated when Turkey shot down a Russian jet near the Syrian border, claiming that it crossed into Turkish territory. When assessing each option, officials need to ask not just, “Will it help defeat ISIS?” but also, “Will it help deliver long-term stability?”

And, for that matter, what does a secure Iraq and Syria even mean? Here, U.S. officials must be realistic about what is achievable. Americans tend to be idealistic, and often go to war with grandiose visions of building a beacon of freedom. These illusions come crashing down due to ignorance of foreign cultures and local resistance to American dreams. Former German Chancellor Otto von Bismarck said that politics is the art of the possible. Clausewitz said that war is a continuation of politics by other means. It follows that war is the art of the possible.

In Syria, the possible may come in the form of ugly stability, or an end state where ISIS and other radical jihadist groups are a manageable problem—to the point where the U.S. and other international forces can gradually be withdrawn from the region. The scale of the destruction in Syria is so vast—with half the Syrian population injured, dead, or displaced—that the U.S. and its allies need to be pragmatic about any peace deal. This means negotiating with all manner of insurgent groups, some of whom have committed atrocities. It means creating a national unity government in Damascus that will likely include elements of the regime and perhaps even Assad himself—at least for a transitional period. It means avoiding a repeat of the mistakes made in Iraq in 2003 by, for example, not suddenly disbanding the state military. It means engineering a political settlement that will enlist Sunnis in the fight against ISIS while protecting the Alawite minority, to which the Assad family belongs, from potential reprisals.

Syria is only half the equation. After ISIS is eventually pushed out of Mosul and Ramadi, who will govern these Iraqi cities, which have been traumatized by months of jihadist rule? And here’s an even bigger question: Is the international community intent on protecting the current borders of Iraq and Syria, or is partition on the agenda?

Even the best outcome in the Middle East won’t feel like victory. We’re looking at months or years of battling ISIS, and then years or decades of stabilizing Syria and Iraq.

Critical decisions are about to be made that could starkly curtail future options. We need to think more like Roosevelt, and less like Tojo. Achieving real success means considering both urgent needs and ultimate goals. The objective is not just to overthrow ISIS, but also to build a new and durable order. Either create a plan to win the peace, or don’t fight at all.

ISIS shouldn’t be the only side thinking about the end times.