Iraq

— — On March 19, 2003, millions of Americans watched as President George W. Bush announced from the Oval Office that Americans and coalition forces had begun military operations inside Iraq against the regime of Saddam Hussein .

In his speech, the president said the goal would be to “disarm Iraq, to free its people and to defend the world from grave danger,” and that “we will accept no outcome but victory.”

But 12 years later President Obama has ordered a U.S. military presence back into Iraq to assist with the fight against ISIS , four years after he oversaw the complete withdrawal of all U.S. troops in December 2011.

ABC News took a look back on the past dozen years and the events and players who shaped one of the more divisive and consequential conflicts in recent history.

THEN: At the start of the 2003 military campaign, Saddam Hussein had been president of Iraq for more than two decades after seizing power in a 1979 Ba’athist party coup. When the U.S. “shock and awe” bombing campaign began in March Saddam escaped Baghdad and went into hiding. A month later, Iraqi citizens aided by U.S. troops brought down Hussein’s statue in Baghdad’s Firdos Square that had been erected for his 65th birthday. The toppling of the statue became one of the war’s most iconic images.

In December 2003, U.S. military forces found Hussein near his hometown of Tikrit hiding in a spider hole in the ground below a two-room mud shack on a sheep farm.

NOW: In December 2006, Hussein was executed after being found guilty of crimes against humanity by an Iraqi Tribunal. Now the Associated Press reports that Hussein’s grave, located outside the city of Tikrit, has been nearly destroyed in the ongoing fight between Iraqi forces and ISIS.

Today Haider al-Abadi is Iraq’s prime minister. He returned to Iraq in 2003 after having spent 30 years in exile, and has struggled to hold together sectarian interests and fend off the rapid advancement of ISIS, which currently controls vast swathes of land in the country’s northwestern region including the second-largest city of Mosul.

THEN: 90,000 U.S. service members were involved in the 2003 ground invasion of Iraq. But by 2007 the number of additional American forces rose to 160,000 as President Bush ordered a surge of troops to help quell the sectarian strife that had consumed Iraq. More than 4,400 U.S. service members lost their lives in Iraq, with more than 33,000 wounded. At least 150,000 Iraqi civilians are estimated to have been killed in the conflict between 2003 and 2013.

NOW: After the ground invasion the U.S. disbanded what was one of the Middle East’s largest armies. Disenchanted former soldiers soon joined the ranks of the insurgency, fueling a spiral of violence that dominated the American occupation. Meanwhile the U.S. struggled for years to rebuild a capable military from scratch. By the time all U.S. military forces left in 2011 American military officials were confident that Iraq’s military had been rebuilt into a professional force. But with no security agreement between the two countries, the Army’s skills and professionalism eroded under the government of Prime Minister Maliki as training was reduced and he replaced Sunni commanders with Shiites. Today 2,875 American service members are in Iraq to advise, train and assist Iraq’s military so it can defeat ISIS.

THEN: In 2003, Iran’s presence in Iraq was virtually non-existent.

NOW: The relationship between the two Shiite -majority countries is tighter than it has ever been. Iran has also taken a prominent position in the country’s fight against ISIS, sending 50 to 60 military advisers to Iraq and helping direct the large offensive on the ISIS held city of Tikrit.

THEN: 12 years ago Hussein’s Sunni-led government oppressed the majority Shiite population for decades.

NOW: The end of the Hussein regime brought democratic elections that shifted the balance of power to Shiites. And after being repressed for decades, sectarian divisions developed into full-scale conflict. Sectarian violence, even at its lowest levels, has become a part of daily life inside Iraq. In 2014, the country suffered the highest number of civilian deaths since 2008.

Former President George W. Bush had a tongue-tied moment at a speech on Wednesday and millions on social media took notice.

When condemning Russia’s attack on Ukraine , Bush mistakenly referred to the decision to launch an “unjustified and brutal invasion of Iraq” before quickly correcting himself to say “Ukraine,” in what was a bungled criticism of Russian President Vladimir Putin.

“The result is an absence of checks and balances in Russia, and the decision of one man to launch a wholly unjustified and brutal invasion of Iraq,” said Bush, before catching himself and shaking his head. “I mean — of Ukraine.”

Realizing his mistake, Bush then appeared to say under his breath, “Iraq, too.”

Bush made the comment in a speech at his presidential center at Southern Methodist University in Dallas on Wednesday during an event examining the future of American elections. After a pause, Bush blamed the mistake on his age and the audience erupted in laughter.

“Anyways, I’m 75,” he added.

But on Twitter, the reaction to Bush’s inadvertent reference to the most polarizing decision of his administration was mixed, as users revived criticism of his decision to invade and sarcastically riffed on his history of such slip-ups .

Former Rep. Joe Walsh, who ran for the Republican nomination for president in 2020, tweeted as the clip swirled through social media: “All gaffes aside, George W Bush was wrong to invade Iraq. And Putin was wrong to invade Ukraine.”

Another user cracked that “Freud really stepped out of his grave to personally slap the ‘Iraq’ out of Bush’s mouth didn’t he.”

The mixup was widely seen. Since video of Bush’s speech was clipped and tweeted by Dallas News reporter Michael Williams on Wednesday, it has been viewed more than 17 million times.

In his Wednesday remarks, Bush also described Ukrainian President Volodymyr Zelenskyy as a “cool little guy,” deeming him “the [Winston] Churchill of the 21st century.”

As president, Bush oversaw the U.S.-led invasion of Iraq in 2003 — as part of the post-9/11 conflicts in the Middle East — under the pretext that the country was hiding weapons of mass destruction, or WMDs. Iraq’s dictator, Saddam Hussein, was deposed but no weapons were found, and the war officially lasted for nearly a decade.

While the Bush administration argued the fighting was necessary for national security even without the WMDs, it became increasingly unpopular at home. Thousands of U.S. service members and tens of thousands of civilians died.

Bush wrote in his post-White House memoir that he had a “sickening feeling” when he learned there were no WMDs in Iraq after their supposed existence was used as justification for the invasion. He told ABC News’ “World News Tonight” when leaving office in 2008 that the “biggest regret” of his presidency was what he called the “intelligence failure in Iraq.”

When pressed in that interview, Bush declined to “speculate” on whether he would still have gone to war if he knew Iraq didn’t have WMDs. “That is a do-over that I can’t do,” he said.

Nonetheless, he wrote in his memoir, “I strongly believe that removing Saddam from power was the right decision.”

ABC News’ Chris Donovan contributed to this report.