When US troops withdrew from Iraq in 2011, US President Barack Obama said his government was "leaving behind a sovereign, stable and self-reliant Iraq." After Osama bin Laden was shot dead, he extolled it as another victory, saying Al Qaeda was "on the run."

It turns out he might have spoken too soon. The terrorist-backed Islamic State in Iraq and Syria (ISIS) dealt a heavy blow to Iraq on Tuesday last week by occupying the nation's second-largest city of Mossul. ISIS, a Sunni offshoot of Al Qaeda, has even advanced to within about 60 miles of the country's capital.

The heavy setback in Iraq is also probably stunning for the US president. On Friday, Obama said he was still reviewing options and would find what action to take on Iraq, but no US troops would be deployed.

Media reports patched together details of how the US-aided and trained Iraqi security forces had chickened out when ISIS militants charged  toward them. They became victims as well as witnesses of the failure of Iraq's post-Saddam national policy.

Washington should have apologized instead of singing its own praises when its troops withdrew from Iraq. The current reversal of the national security situation of Iraq demonstrates that compared with its high capability to destroy an anti-US regime, Washington is much less qualified to build a new peaceful and democratic system out of the ashes. Terrorism and religious conflicts were unleashed to resurrect and thrive.

As to the US, military withdrawal from Iraq and Afghanistan means its strategic objectives have been accomplished.

Without the support of regional anti-US powers, the capability of terrorists has been much reduced. By successfully driving two wedges into the Middle East, the US can be more manipulative without showing its mere presence.

It seems to be an impossible mission for a hotspot like the Middle East to set up a stable regional framework. The vulnerable and unsteady political structure, which always swung toward terrorism incidents and religious disputes, was shattered by US interventions in Afghanistan and Iraq.

Without finding qualified forces to fill the power vacuum, Obama decided to withdraw and so acquire more bargaining chips on Capitol Hill. But the entire area was left to undergo a dangerous and disoriented power reshuffle all on its own.

It is hard to say where Iraq and the rest of the Middle East is heading. But once a new balance forms, it will possibly be a new nightmare for the US.