The world is on pins and needles as Iraq plunges deeper into crisis. On Monday, insurgents seized the strategic city of Tal Afar near the Syrian border following the seizure of large swaths of Iraq’s northern territories, including the fall of the major cities Mosul and Tikrit last week. The insurgent groups, spearheaded by militants from the Islamic State of Iraq and the Levant (ISIL), an al-Qaida breakaway group, also staged a fierce onslaught across Iraq.

The worsening security situation in Iraq is worrying as the country now bears every emblem of a full-blown sectarian war. With the Syria crisis unsolved, the region is too fragile to see another country fall into the quagmire of bloodbath.

The insurgency of al-Qaida forces in Iraq does not happen overnight. Since the United States withdrew its military forces in 2011, never has a day passed without bloodshed in the Middle East. The pullout of US forces has apparently left a security vacuum in which the Iraqi government is barely capable of self defense. Sectarian clashes become acute day by day, Iraq’s security forces are incompetent in dealing with the infiltration of terrorists from neighboring countries and radical groups have seized the country’s sectarian rifts to expand their own influence there.

The disturbing situation in Iraq has revived public debate about the aftermath of the Iraq war in the world arena, the US included. More and more Americans, politicians included, believe the US invasion of Iraq was the reason behind the revival of al-Qaida forces in Iraq. It is high time Washington squarely faced its legacy of war in Iraq and does whatever it takes to clean up the big mess it left behind in Iraq.

The US owes the Iraqis as well as the rest of the world a convincing explanation as to why it has failed to weed out all the terrorist cells in Iraq after a war that had lasted for eight years. It must take concrete actions to deliver the promises on self-governance, peace and stability it made to the Iraqi people when pulling out its troops from the country.

Washington should also conduct a serious soul-searching about its Middle East policy as the crisis in Iraq clearly marks the failure of the US policy in the region. Even when US President Barack Obama basked in the victory of bringing US troops back home from Iraq, insightful people around the world began to warn that there was no guarantee that Iraq would not become a flashpoint in the region some day in the future. Today that worry is unfortunately coming true.

In a foreign policy speech delivered at the US Military Academy in West Point in May, an ambitious Obama said that by virtue of its economic power, unmatched military, values and spirit of innovation, America will remain the world’s “exceptional” leader.

The on-going crisis in Iraq could be a touchstone of the US’s ability to lead the world. Leadership should be earned, not self-proclaimed. A country that intends to lead the world should always do the right thing and do it right.

The author is a senior writer with China Daily.

wanghui@chinadaily.com.cn