When the last U.S. troops left Iraq in 2011, the American combat role in that country came to an end after nine years of fighting.
The U.S. left behind an Iraqi army largely trained and armed by the U.S. and a country mostly at peace at the expense of 4,480 dead U.S. soldiers, more than 32,000 others wounded and a cost the U.S. more than $700 billion.
Today, the U.S. dropped bombs again on insurgent forces in Iraq as the country is threatened by the forces of ISIS, an al-Qaeda offshoot intent of establishing a caliphate - an Islamic country - in Iraq and neighboring Syria.
Here's a look back at how the situation in Iraq has spiraled out of control since the last American troops departed:
Dec. 15, 2011: U.S. declares end of mission in Iraq
In a small ceremony in Baghdad, the U.S. military formally ended its mission in Iraq after nearly nine years of war. "This is not the end, but the beginning," Defense Secretary Leon Panetta told a small group of U.S. service members and dignitaries gathered to watch the "casing" of the flag of U.S.-Forces-Iraq.
July 23, 2012: Obama touted ending the war in Iraq on bloody day
President Obama's reelection campaign released a video praising the president for ending the war in Iraq on what proved to be the deadliest day of the year in that country. Abu Bakr al-Baghdadi, al-Qaeda's top leader in Iraq, released an audio message announcing, "We are setting off a new stage of our struggle, with the launch of a plan named 'breaking the walls.'"
March 19, 2013: 10th anniversary of Iraq invasion
The 10th anniversary of the start of the U.S. war in Iraq was a muted affair with no official commemorations in either Washington or Baghdad. The anniversary is marred in Iraq by a wave of bombings that killed at least 59 people in Baghdad and injured 221 others.
January 2014: ISIS Forces Take of Fallujah
The predominantly Sunni city in western Iraq was overrun by ISIS. The city had previously been taken by U.S. Marines in one of the bloodiest battles of the Iraq war. Iraq vows to take back the city. Instead, ISIS moves on to take part of the city of Ramadi.
Jan. 17, 2014: U.S. in talks to train Iraqi forces
The Pentagon announced "discussions" with Iraq about the possibility of training Iraq's security forces. Instead, Iraqi security forces receive training in Jordan from other countries in the region.
June 11, 2014: ISIS tightens its grip
In a shocking blitzkrieg, ISIS chased the Iraqi army out of Mosul and swept south to take Tikrit and menace Baghdad. ISIS is aided by Sunni tribes and former members of the Saddam regime.