In his 2002 State of the Union Address, President George W. Bush describes "regimes that sponsor terror" as an Axis of Evil, in which he includes Iraq, Iran and North Korea.
In October 2002, Bush signed a congressional resolution authorizing war against Iraq.
In February 2003, Secretary of State Colin Powell presented evidence to the United Nations Security Council that Iraq had biological weapons and argues in favor of military action. Powell later admitted he had presented what turned out to be an inaccurate case to the UN on Iraqi weapons, and the intelligence he was relying on was, in some cases, "deliberately misleading."
Bush announced the start of the war between Iraq and the U.S. during a televised address from the Oval Office on March 19, 2003. The United States said it had began its war against Iraq just minutes after several explosions were heard over Baghdad.
In an operation dubbed "Shock and Awe," smoke billowed from a presidential palace compound in Baghdad during air strikes on March 21, 2003. Large explosions shook Baghdad during a night of blistering air strikes, as U.S. and British ground forces advancing across southern Iraq battled for hours for control of a strategic airfield.
U.S. troops wait in the toilets and shower rooms wearing full nuclear biological and chemical protection suits in during an air raid warning in Kuwait on March 21 2003. Men showering scrambled to get into their protection as the sirens sounded.
A Tomahawk cruise missile rises in a plume of smoke as it is fired from the MK-41 vertical launching system and lights up the U.S. flag and a banner which reads, 'We Shall Never Forget' on board the Aegis guided missile cruiser USS Mobile Bay on March 24, 2003.
A U.S. Army combat engineer enjoys a cigarette as he relaxes between the cities of Najaf and Karbala as another sandstorm turns the daylight orange on March 26, 2003.
A U.S. Marine with Fox Company 'Raiders' patrols in Nassiriya in southern Iraq on April 8, 2003.
Baghdad fell to U.S. forces on April 9, 2003. Here, U.S. Marine Corp Assaultman Kirk Dalrymple watches as a statue of Iraq's President Saddam Hussein falls in central Baghdad. The head was later removed and dragged through the streets.
U.S. Marines from Lima Company, a part of a 7th Marine Regiment, walk in front of the Martyrs Monument during the operation of securing the center of Baghdad on April 9, 2003.
Combat camera video shows undated footage of U.S. Army soldier Jessica Lynch on a stretcher during her rescue from Iraq. The video was shown as part of a media briefing at Camp As Sayliyah on April 2, 2003. Lynch was severely injured and then kidnapped when her convoy was ambushed on March 23, 2003, by Iraqi forces during the Battle of Nasiriyah.
U.S. Army Spc. Shoshana Johnson is transported onto a Marine helicopter with six other U.S. prisoners of war on April 13, 2003. Johnson, along with Lynch, was kidnapped during an ambush and held captive for 22 days. Johnson suffered gunshot wounds to both of her ankles.
U.S. Marines kick in a door while securing a building next to the main hospital in central Baghdad on April 15, 2003, which will be used as a temporary Iraqi police headquarters.
In a now infamous moment, Bush told a cheering crew aboard the USS Abraham Lincoln on May 1, 2003, thatU.S.forces had brought about a "turning of the tide" against terrorism. Underneath a banner reading “Mission Accomplished,” the president said the conflict with Iraq marked the beginning of “a new era” in waging war.
Capt. Christopher Fallon from Orlando, Fla., of the 1st battalion of the 22nd regiment of the fourth division of the U.S. Army plays baseball in one of the palaces of ousted Iraqi dictator Saddam Hussein in Tikrit, about 110 miles northwest of Baghdad, on Sept. 16, 2003.
In 2003, protests against the Iraq War take place in more than 600 cities worldwide. It is estimated that between 8 million to 30 million people participate, making this the largest peace demonstration in history.
On Dec. 13, 2003, troops found a haggard Hussein hiding in a spider hole outside a farmhouse near his hometown of Tikrit. They managed to capture the elusive dictator without firing a shot following an eight-month manhunt.
British Army troops are covered in flames from a petrol bomb thrown during a violent protest by job seekers, who say they were promised employment in the security services, in the southern Iraq city of Basra on March 22, 2004. As the protest evolved into violence, demonstrators were heard to chant, "Yes yes to Yassin, no no to America, Britain and Israel" in response to the killing in Gaza of Hamas founder and spiritual leader Sheikh Ahmed Yassin.
Coffins of U.S. military personnel are prepared to be offloaded at Dover Air Force Base in Dover, Del., in this undated photo. The U.S. Air Force, in response to a Freedom of Information Act request, released more than 300 photos showing the remains of U.S. service members returning home to the website www.thememoryhold.org on April 14, 2004.
A picture obtained by ABC News and released May 19, 2004, shows a man identified as Sgt. Charles Graner posing over the body of detainee Manadel a-Jamadi in the now-infamous Abu Ghraib prison. The Justice Department opened an investigation into this death and four others, and the Defense Department removed 17 soldiers and officers from duty. Graner and his former fiancee, Specialist Lynndie England, were sentenced to 10 years and three years in prison, respectively, for their roles in the abuse.
In November 2004, more than 10,000 U.S. troops and a small number of Iraqi army units begin a siege on the insurgent stronghold of Fallujah, Iraq. Dubbed Operation Phantom Fury, the siege would last until Dec. 23 and result in the death of more than 1,350 insurgent fighters and 95 American soldiers. The operation would prove to be the bloodiest battle of the Iraq War.
U.S. Marine platoon Gunnery Sergeant, Ryan P. Shane (C), from the 1st Battalion of the 8th Marine Regiment, and another member pull a fatally wounded comrade to safety while under fire during a military operation in the Iraqi western city of Falluja on Dec. 17, 2004. Seconds later, Shane was also injured by nearby enemy fire, a U.S. Marine officer said.
An Iraqi woman rests as she waits with other women to cast her ballot in Najaf in Iraq's first national election on Jan. 30, 2005. Millions of Iraqis flocked to vote in a historic election, defying insurgents who killed 35 people in a bloody assault on the poll.
On Nov. 23, 2006, a series of fiery suicide car bombings killed at least 152 people and injured 236 more in the deadliest sectarian attack in Baghdad since the war began.
In November 2006, Hussein and his co-defendants Barzan Ibrahim al-Tikriti and Awad Hamed al-Bandar are sentenced to death for crimes committed against residents of Dujail, Iraq, in 1982, following a failed assassination attempt against Hussein. Specific charges included the murder of 148 people, torture of women and children and the illegal arrest of 399 others.
Footage from Al Iraqiya television shows masked executioners putting a noose around Hussein's neck moments before his hanging in Baghdad on Dec. 30, 2006. Hussein was hanged for crimes against humanity at dawn in a dramatic, violent end for a leader who ruled Iraq by fear for three decades.
In response to rising violence, Bush announces in a televised address to the nation on Jan. 10, 2007, that he will send a "surge" of 21,500 U.S. forces to Iraq.
Demonstrators wave Iraqi flags during an anti-U.S. protest called for by fiery cleric Moqtada al-Sadr in Najaf, marking the fourth anniversary of the fall of Baghdad on April 9, 2007. Baghdad was under curfew on Monday on the fourth anniversary of the fall of the capital to U.S. forces.
In a lighter moment, U.S. soldiers push the car of an Iraqi man to start the engine at a checkpoint in north Baghdad on June 13, 2007.
On Sept. 17, 2007, controversy erupts after contractors for the private security firm Blackwater shoot 17 Iraqi civilians in a Baghdad square. Here, a man who was wounded in the attack is helped by his relatives in a Baghdad hospital. Irate Iraqi officials canceled the controversial firm's license, although ultimately all charges against Blackwater are dismissed.
An Iraqi woman reacts as men are taken out of a house and detained by U.S. soldiers of the 2nd Brigade, 1st Armour Division, and Iraqi soldiers during a joint military operation in Baghdad's Sadr City on July 12, 2008.
On Dec. 14, 2008, Bush is almost struck by two shoes thrown at him by Iraqi journalist Muntadhar al-Zaidi during a news conference in Baghdad. In March 2009, al-Zaidi would be sentenced to three years in prison for assaulting a foreign head of state during an official visit. The sentence was later reduced to one year and al-Zaidi was released on Sept. 15, 2009, for good behavior after serving nine months of the sentence.
On Jan. 1, 2009, U.S. troops formally hand over military control of Baghdad's heavily-fortified Green Zone to Iraqi troops, a first major step in the U.S. withdrawal from Iraq.
Iraqi policewomen aim their weapons during training at a police academy in Kerbala, 50 miles southwest of Baghdad, on March 22, 2009. About 2,000 policewomen participated in the three-month training course.
On Jan. 25, 2010, Iraqi officials hang Ali Hassan al-Majeed, the Saddam Hussein henchman widely known as "Chemical Ali," for genocide against ethnic Kurds. The cousin of Hussein, he laughed as his guilty verdict was read.
President Barack Obama declares an end to conflict in Iraq during a national address from the Oval Office on Aug. 31, 2010.
On Dec. 17, 2011, a U.S. military vehicle crosses the border into Kuwait as the last convoy of U.S. soldiers pull out of Iraq, ending nearly nine years of war that cost almost 4,500 American lives.
Supporters of anti-U.S. Shi'ite cleric Moqtada al-Sadr wave Iraqi flags during a rally in Basra on March 19, 2012. The protest marked the ninth anniversary of the start of the U.S. invasion in 2003. Slogans were mainly directed at the government of Prime Minister Nuri al-Maliki for failing to improve the lives of Iraq's poor.
In June 2014, Islamic militants overran the city of Mosul after taking Fallujah earlier in the year, sending residents and even security forces fleeing. They were threatening to march further south into Baghdad, putting the country's relative stability at risk.
In August 2014, President Barack Obama announced that U.S. airstrikes had begun on Islamic militants after the group had advanced toward what Obama called U.S. interests in northern Iraq. Humanitarian aid drops were also underway to the ethnic Yazidis stranded in the northern mountains by the Islamic group's military siege.