Flags fly at half staff at the Washington Monument in Washington, D.C.Kevin Lamarque / Reuters

Before Saturday night’s debate, the Democratic presidential candidates had only a day to prepare for terrorism’s new centrality to the 2016 campaign. And it showed. Bernie Sanders rightly noted that both the Iraq War and climate change had contributed to the political breakdown on which ISIS feeds. But when it came to outlining a vision for fighting the Islamic State going forward, none of the candidates ventured much beyond platitudes. Hillary Clinton backhandedly admitted as much when she promised that, “I will be laying out in detail what I think we need to do with our friends and allies in Europe and elsewhere to do a better job of coordinating efforts against the scourge of terrorism.” Given that Clinton announced her presidential bid in April, and months ago delivered policy speeches on a variety of domestic subjects, the fact that she hasn’t provided that detail yet shows how absent terrorism has been from the Democratic campaign.

Both politically and morally, that’s dangerous. The Republican line on ISIS’s attacks in Paris is clear: The United States left Iraq, and the larger Middle East, because Barack Obama doesn’t believe in American power, and now “radical Islam” is taking over the region and coming after Americans. So the U.S. must “lead” again, which means more bombing, a no-fly zone in Syria, tearing up the Iran nuclear deal, a harder line against Russia, and no admission of Syrian Muslim refugees to the country. If the Democrats don’t offer an alternative vision, and instead stick to generalities while waiting for the conversation to turn back to domestic affairs, the trust gap separating the two parties on national security will grow.

A Democratic response to Paris should start by noting that while Americans today feel some of the same fear and rage they felt after the 9/11 attacks, they also know that President George W. Bush exploited that fear and rage to do disastrous things. In the ISIS era, America must not repeat those mistakes.

The first mistake was Bush’s decision to make the “war on terror” a war against virtually every movement and regime in the greater Middle East with whom the United States had a beef, whether they were connected to 9/11 or not. For Bush, who repeatedly compared the “war on terror” to World War II, responding to 9/11 by merely going after al-Qaeda was “small ball.” So the United States invaded and occupied Afghanistan and Iraq while simultaneously intensifying its cold war with Iran. This satisfied the public’s desire for a response equal to the magnitude of the crime. But it cost the United States trillions of dollars and thousands of lives, and left it in a far weaker position in the world than before 9/11.

Bush’s mentality still dominates the GOP. Most of the Republicans running for president want the United States to declare war on “radical Islam,” an amorphous term that blurs the distinction between ISIS and those Islamist governments, for instance in Iran and Turkey, with which ISIS is at war.

The Democrats should note that America’s wisest presidents have done the opposite. They’ve defined America’s enemies narrowly, even when that means cooperating with nasty regimes, so as to give the United States the best chance of success. Franklin Roosevelt didn’t fight a war against totalitarianism: He allied with Stalin’s Soviet Union against Nazi Germany. Despite his anti-communist rhetoric, Harry Truman aided Yugoslavia’s communist leader, Marshal Tito, because Tito was resisting Soviet domination of Eastern Europe. Richard Nixon cozied up to an even more powerful communist regime, China’s, to increase America’s leverage over the U.S.S.R. During the Gulf War, George H.W. Bush didn’t declare war on Baathism: He brought one Baathist dictator, Hafez al-Assad in Syria, into the coalition against another, Saddam Hussein in Iraq.

Real foreign-policy seriousness, as opposed to the pseudo-seriousness peddled by hawks like Marco Rubio and Jeb Bush, requires priorities. The Democratic candidates should say their priority is destroying ISIS because it is ISIS—not Iran and not Russia—that is plotting mass murder in America. They should pledge to work with Russia and Iran, along with Saudi Arabia and Turkey, to build the military capacity to do that. And if that means accepting some Russian and Iranian influence in a future Syria, so be it. The United States should do everything it can diplomatically to end Syria’s civil war, so that the factions and regimes now warring against each other can turn their guns on ISIS. Given the deep animosity between Saudi Arabia and Iran, that will be awfully hard. But it’s still far more plausible than the GOP vision, which is to amp up America’s cold wars with Iran and Russia in the hope that the U.S., without ground troops, can push Tehran, Moscow, and ISIS out of Syria all at the same time.

The second lesson today’s Democratic candidates should learn from 9/11 is that when you’re fighting a war against terrorists who claim that the West is abusing and insulting Muslims, it’s not smart to abuse and insult Muslims. George W. Bush built an anti-terror prison at Guantanamo Bay because he believed the United States could not safely accord accused terrorists due process. But in the years since, the abuse of Guantanamo prisoners, and the hunger strikes those prisoners have launched in response, have become bonanzas for jihadist recruitment. Air Force Officer Matthew Alexander has reported that the insurgents he interrogated in Iraq frequently mentioned Guantanamo as a source of their rage. Anwar al-Awlaki, the Yemeni cleric who influenced Fort Hood shooter Nidal Hasan, spoke often about Gitmo. That’s why Republicans who actually come from the U.S. military, like Colin Powell and David Petraeus, want the prison closed.

Today’s GOP candidates, by contrast, seem intent on boosting ISIS recruitment in ways Bush could not have imagined. Ben Carson says Islam is not “consistent with the Constitution” (which is what ISIS believes too); Donald Trump encourages a questioner who asks whether America can “get rid” of Muslims. And now, after the Paris attacks, virtually all the GOP candidates want to bar America’s doors to Muslim refugees, despite the fact that America has admitted hundreds of thousands of refugees from the Middle East since 1980 and not seen a single one commit terrorism.

Obviously, ISIS will feel no less murderous toward America if America welcomes Muslim refugees. But the battle is not to win over members of ISIS. It’s for the hearts and minds of those American Muslims who will be less susceptible to ISIS propaganda if they feel like full citizens in the United States. For jihadist propaganda purposes, a candidate like Ted Cruz, who says the U.S. should accept only Syrian Christian refugees, is a blessing. If he didn’t exist, ISIS would try to invent him.

Democrats can hold their own on terrorism. Barack Obama showed that in his race against Mitt Romney in 2012. But they need the knowledge and self-confidence to articulate their own vision, and to defend it from GOP attack rather than change the subject. Perhaps Hillary Clinton, Bernie Sanders, and Martin O’Malley didn’t have time to develop such a vision in between the Paris attacks and last Saturday’s debate. But the next time, they’ll have no excuse.

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