The spectre of Iraq continues to haunt the American people. How else to explain their reluctance to support sending US ground troops to Syria?

Since the Paris atrocities, Americans have declared solidarity with their French allies. A UN Security Council resolution has called on the world to take “all necessary measures” to fight what it says is a “global and unprecedented threat to international peace and security”. Polls show that the American people are more worried about the threat of Islamic fundamentalism than at any time since 2002.

Yet Americans are reluctant to support “boots on the ground” to extinguish Islamic State from the Middle East. According to a Reuters/Ipsos poll a week after Paris, 76 percent oppose combat soldiers in Iraq and Syria. Neither the Democrats nor Republicans support ground troops.

Why? Why are Americans so dovish when the moment of truth arrives?

The answer lies in understanding the American psyche in the wake of the foreign-policy quagmires in Iraq and Afghanistan.

Go back to 2008. Five years after Iraq, a war that had cost the US dearly in blood, treasure and credibility, the public mood had turned so decidedly non-interventionist that even a dovish liberal Democrat won both his party’s nomination and the general election against his more hawkish rivals.

According to Gallup in August 2007, 81 percent of Democratic voters said the Iraq war, which Hillary Clinton had supported, was a mistake. Barack Obama also won the presidential election against John McCain, the darling of Republican hardliners, largely because he promised to end the war. According to a March 2008 Washington Post-ABC News poll, two-thirds of Americans said the war was one not worth fighting.

Obama’s decision to withdraw troops from Iraq in December 2011 was warmly welcomed by the American people. In October of that year, Gallup showed 75 percent support.

The message: the US had become less inclined to intervene in global trouble spots and more pre-occupied with economic problems at home.

No wonder foreign policy was the dog that did not bark in the 2012 presidential election. One of Obama’s campaign themes, “nation building must begin at home,” reflected popular sentiment. In his 40-minute speech at the Republican national convention, Obama’s rival Mitt Romney devoted only one paragraph to foreign affairs. During the October foreign-policy debate, both Romney and Obama were keen to pivot to domestic affairs while warning about getting bogged down in another Middle Eastern quagmire. At one point, Romney warned, ‘We can’t kill our way out of this mess’.

Public opinion did not turn against Obama’s foreign policy until mid-2013. The administration’s vacillation and ineptitude over how to handle Syria’s President Bashar al-Assad in the civil war damaged US credibility and prestige. President Obama drew “red lines” (Syria’s use of chemical weapons) but failed to execute the threatened air strikes after Washington’s warnings went unheeded. Obama was caught flatfooted, though the substance of his decision was sound. After all, the removal of the Assad regime would have created strategic vacuums for Sunni jihadists, including Islamic State, to fill.

Still, by 2014, the Pew Research Centre had reported that 52 percent of Americans believed the U.S. should “mind its own business internationally”. That figure was the highest such total in the nearly 50-year history of that survey. Similar polls represented an anti-interventionist current that was sweeping across party lines. ‘America,’ the distinguished New York Times columnist Bill Keller declared, ‘is again in a deep isolationist mood’.

All that dramatically changed when in 2014, Islamic State’s carefully choreographed videos of barbaric beheadings of hostages in August and September spooked Americans. Suddenly, they were taunted and goaded out of their torpor by the Islamist jihadists.

From that moment, polls showed a more hawkish world view. By September, a Wall Street Journal/NBC News poll showed that two-thirds believed it was in the national interest to confront Islamic State in Iraq and Syria. Only 13 percent opposed. Ever since, Obama has been under attack for failing to provide assertive global leadership and both Republicans and Democrats have supported a more active role on the world stage.

And yet Americans oppose sending significant numbers of combat soldiers. True, 3,500 ground troops and 50 special operations troops are already based in Iraq and Syria. But given that air power alone evidently will not defeat Islamic State, most military experts agree about a hundred thousand ground troops and a political settlement is needed in order to create a post-war peace. In reality, there is neither.

The upshot is that although Americans are outraged by Islamic State, especially in the wake of the Paris atrocities, there is a strong public aversion to seeing US soldiers killed and wounded in endless local conflicts in vast regions deeply hostile to western military intervention. To the extent that such attitudes prevail, they are inimical to the notion of American global leadership, a Pax Americana or the American Century: buzzwords that so many US presidential candidates advocate on the campaign trail.

Instead, it’s a fair bet the American people – instinctively, at least – are more attracted to old-fashioned statecraft, brilliantly expressed by the legendary public intellectual Walter Lippmann:

Without the controlling principle that the nation must maintain its objectives and its power in equilibrium, its purposes within its means and its means equal to its purposes, its commitments related to its resources and its resources adequate to its commitments, it is impossible to think at all about foreign affairs.

By wilfully ignoring the principle that ends must have some relation to means in the post-911 era, a huge gap opened between America’s global pretensions and its ability to finance them. That is a gap the next President should be intent on closing.

Tom Switzer is a research associate at the University of Sydney’s United States Studies Centre and host of Between the Lines on ABC’s Radio National. This article can be republished with attribution under a Creative Commons License.