HOW IRAQ IMPLODED
December 2011: U.S. troops complete withdrawal; Iraq's Shiite government issues arrest warrant for Sunni vice president, prompting a political crisis.
December 2012: Major protests begin in Sunni areas demanding Prime Minister Nouri al-Malaki's ouster.
January 2014: Iraq loses control of Fallujah and other regions to Al-Qaida-linked fighters in the Islamic State in Iraq and the Levant (ISIL).
April 2014: Al-Maliki wins the most seats in a general election, but his alliance falls short of a majority.
June 2014: ISIL forces seize Mosul and the province of Nineveh and head south toward Baghdad. The government and top clerics implore Shiites to take up arms. President Obama sends up to 300 military advisers to Iraq.