Andrew Bacevich argues at Politico that President George W. Bush and his administration share responsibility for the migrant crisis that is now overwhelming Europe. After “breaking” Iraq, the United States adamantly refused to accept anything like ownership of the consequences stemming from the recklessly misguided invasion, he writes.

That is a bit unfair but also not entirely wrong.

The United States did try to keep Iraq together through eight years of occupation and at the cost of nearly 4,500 lives.

But no effort could repair the damage done by the war in the first place.

Bush’s successor, Barack Obama, gave up on Iraq and is now doing little to help his European allies cope with the influx of hundreds of thousands of refugees from the Middle East. His government has said it will let in 10,000 Syrians, one-eightieth the number Germany is admitting. Bacevich sees this as a sign of “pronounced indifference” to the humanitarian crisis.

The United States do contribute to the sheltering of refugees in the region and are bombing targets of the self-declared Islamic State in Iraq and Syria. The group has compelled many who do not share its unforgiving interpretation of Islam to flee. But those efforts are at best halfhearted while the West as a whole has done little to hasten the demise of Syria’s dictator, Bashar al-Assad.

It is doubtful if Assad’s fall would, in the short term anyway, ameliorate the crisis. But the fact that the world is in this dilemma in the first place — whether to risk worse conflagration in the wake of Assad’s demise or allow him to butcher his own people — owes a lot to American policy.

Bacevich admits it would be misleading to attribute the refugee crisis to any single cause.

A laundry list has contributed: historical and sectarian divisions within the region; the legacy of European colonialism; the absence of anything even approximating enlightened local leadership able to satisfy the aspirations of people tired of corruption, economic stagnation and authoritarian rule; the appeal — inexplicable to Westerners — of violent Islamic radicalism. All play a role.

Some go so far as to blame the European dismantling of the Ottoman Empire after World War I; something that his website has argued overlooks Arab agency and is counterproductive.

The more immediate cause, as Bacevich points out, is indeed the 2003 invasion of Iraq.

Saddam Hussein was a brutal tyrant but at least kept a lid on the region’s sectarian cleavages and unmet aspirations of his people. The George W. Bush Administration “blew off that lid,” according to Bacevich, “naively expecting liberal democracy or at least deference to American authority to emerge.”

In toppling Hussein, the United States empowered Iran, aggravating a regional power struggle between the region’s largest Shia state and its Sunni rivals; exacerbated broader Shia-Sunni misgivings; exposed the region’s military-backed strongmen as far more vulnerable than their populations had thought; and set a precedent for well-intentioned regime change.

On a smaller scale, the Obama Administration tried the same in Libya in 2011. In that case, too, the United States “broke” the country and left — and now Europe must cope with the consequences: hundreds of thousands of refugees crossing the Mediterranean this year, thousands of them drowning, overwhelming European institutions in the process and dividing European societies between those who argue that a wealthy continent must help those in need and others who caution that admitting so many asylum seekers from an alien culture and economically and politically backward region will have a negative effect on their society.

The only difference was that in Libya, many European countries — not Germany — called for intervention while most opposed the Iraq War.