PARIS — Who lost Iraq? There are only three possible answers to that question: George W. Bush, Nouri al-Maliki, Barack Obama. The former American president sinned with pride, the Iraqi Prime Minister with sectarianism and the current U.S. president with indecision.

Democracy in Baghdad will bring peace that stretches to Jerusalem — so predicted the “Democracy Bolsheviks” who had a decisive influence on the choices of the Bush administration. The war in Iraq is the direct product of the wishful thinking that mistook the 2003 Middle East for 1944 Europe.

The fall of Mosul last week, which happened with virtually no resistance, is the most spectacular proof of the patent failure of the Bush administration's ideological approach of the Middle East. The toppling of Saddam Hussein’s regime did not result in the victory of democracy, but in the implosion of a country, and the challenging of the longstanding borders of an entire region.

The Islamic State in Iraq and the Levant (ISIS) jihadists have deliberately erased the — largely artificial — borders set by the 1916 Sykes–Picot Agreement, which separated Syria from Iraq to form a sort of “Sunnistan.” They now control an area that goes from the Syrian city of Aleppo to northern Iraq’s Mosul. A refuge for terrorists has been formed in the heart of the Middle East, while the U.S. is about to withdraw from Afghanistan, as it already has from Iraq.

Are the reasons to intervene today not more real than those from yesterday? The jihadists are a reality, unlike the weapons of mass destruction that Saddam Hussein was supposed to have. It is not about protecting a people from its dictator anymore, but an entire region from the destabilizing control of a radical ideology. But yesterday’s failures weigh heavily on today’s decisions.

After winning the war, George W. Bush’s America was only bound to lose the peace. Overly ambitious goals, a poorly thought military strategy, allocated means that were too limited: One could be tempted to say that the U.S. and, behind it, its allies with Tony Blair’s Britain at the forefront, "had it all wrong."

By sending home all the civilian and military Sunni executives of Saddam Hussein’s regime, Washington doomed itself to unavoidable failure. It is interesting to note that Maliki’s regime merely followed the American model, when it too excluded all Sunnis from running the country.

The U.S. did not manage to rebuild a credible army despite the amount of money wasted on it. It was a disastrous choice for the U.S. military to count on essentially quantitative, rather than qualitative, standards to rebuild the Iraqi army. The American soldiers were too few to compensate for the inexperience and the unwillingness of the Iraqi soldiers.

First things first

The corruption of the regime started with the corruption of the security services. The army was not the expression of the nation; it did not feel responsible for the security of a country and its inhabitants. Before anything else, it intended to protect its own interests. Hence its rapid collapse against an enemy far smaller in number but infinitely more motivated.

From the failed state that Iraq has become in the hands of a sectarian, corrupt and ineffective leadership — and with a sort of ripple effect — we are witnessing a shifting of alliances that, in reality, aims to fill in the void left by the U.S. By alternating, in such a short period of time, between excessive historical will under Bush and Obama's overly cautious resignation in the face of a rapid disintergration on the ground, the U.S. has left the region without any basic semblance of order or guarantees for the future.

By overthrowing Saddam Hussein in Iraq yesterday, the U.S. had provided an easy victory to its Shia rivals behind Iran, thus weakening its traditional allies, the Sunni Gulf monarchies. Since then, the U.S. has first abandoned Hosni Mubarak’s regime in Egypt, and after hesitating on Mohamed Morsi’s Muslim Brotherhood, backed Abdel Fattah al-Sisi’s rise to power.

In the same way, the U.S. seems to be giving in to Israel pursuing its settlements in the West Bank and a de facto acceptance that any kind of peace process in the region is destined to die.

Finally and most importantly, the U.S. has decisively brought its credibility into question by resigning to allow Bashar al-Assad’s regime to stay in place in Syria, even though it used chemical weapons, in large quantities, against its people.

But nature loathes emptiness, and people are scared of wrecked situations. The victory of the jihadists in Iraq was too fast and too complete not to trigger chain reactions. Can the collapse of Mosul lead to the acceleration of an already ongoing rapprochement between Tehran and Washington? Against the threat of Sunni fundamentalism, can Iran and Saudi Arabia rediscover common interests despite “existential” differences?

One thing is sure: In the space of a few months, from the Middle East to Ukraine and the East China Sea, the priorities of the world have shifted. It is no longer about improving global governance, but about confronting the outbursts of religious or nationalist ideologies — and ultimately, the return of power politics. To face the Islamist radicals threatening Baghdad, a “Holy Alliance” of the least radical, most moderate, forces needs to be established. And it must start with the use of U.S. air strikes against the jihadists.