The 2003 invasion of Iraq marked the initial, swift phase of the broader Iraq War, a conflict that deeply reshaped the geopolitical landscape of the Middle East. This intensive invasion stage commenced on March 19, 2003, with an aerial bombardment, followed by ground operations on March 20. Lasting just over a month, encompassing 26 days of major combat, the invasion saw a formidable coalition of forces from the United States, the United Kingdom, Australia, and Poland sweep into Iraq.

A mere 22 days after the initial incursions, the capital city of Baghdad fell to Coalition forces on April 9, 2003, following a six-day intense engagement known as the Battle of Baghdad. This early, decisive period of the war officially concluded on May 1, 2003, when then-U.S. President George W. Bush famously declared the "end of major combat operations" during his "Mission Accomplished" speech aboard the USS Abraham Lincoln. In the aftermath, the Coalition Provisional Authority (CPA) was established, serving as the first of several transitional governments that ultimately paved the way for Iraq's first parliamentary election in January 2005. U.S. military forces, however, would maintain a presence in Iraq for many more years, finally withdrawing in 2011.

Forces Deployed and International Perspectives

During this initial invasion phase, which stretched from March 19 to May 1, 2003, the U.S.-led coalition committed approximately 160,000 troops. The overwhelming majority, about 73% or 130,000 soldiers, were American. British forces contributed a significant 45,000 soldiers (25%), while Australia provided 2,000 troops (1%), and Poland deployed 194 soldiers (0.1%). Beyond these primary invading nations, thirty-six other countries later became involved in the post-invasion stabilization and reconstruction efforts. In the months leading up to the invasion, a substantial U.S. military buildup saw 100,000 troops assembled in Kuwait by February 18. The coalition also received crucial support from the Peshmerga, Kurdish fighters operating in Iraqi Kurdistan, further complicating the tapestry of forces at play.

Rationales, Doubts, and Global Opposition

The stated objectives for the invasion, articulated by U.S. President George W. Bush and UK Prime Minister Tony Blair, centered on a triad of goals: to disarm Iraq of alleged weapons of mass destruction (WMDs), to end Saddam Hussein's purported support for terrorism, and to liberate the Iraqi people. Yet, these justifications were met with considerable skepticism, as a United Nations inspection team had declared, just prior to the invasion's commencement, that it had found absolutely no evidence of existing WMDs. Other analysts and policymakers often placed greater emphasis on the profound impact of the September 11 attacks, viewing them as a catalyst that fundamentally altered U.S. strategic calculations and spurred the rise of a more assertive "freedom agenda" in foreign policy. For Tony Blair, a key "trigger" for military action was Iraq's perceived failure to seize a "final opportunity" to disarm itself of what U.S. and British officials repeatedly described as an immediate and intolerable threat to world peace posed by alleged nuclear, chemical, and biological weapons capabilities.

Public opinion in the United States ahead of the war was complex and divided. A January 2003 CBS poll indicated that 64% of Americans approved of military action against Iraq. However, a significant 63% simultaneously desired President Bush to pursue a diplomatic solution rather than resort to war, and 62% expressed concerns that a war would, paradoxically, increase the threat of terrorism directed against the U.S. Internationally, the invasion of Iraq faced strong opposition from several long-standing U.S. allies, including the governments of France, Canada, Germany, and New Zealand. Their leaders adamantly argued that there was no credible evidence of weapons of mass destruction in Iraq and that, in light of UNMOVIC's report on February 12, 2003, invading the country was simply not justified. While approximately 5,000 chemical warheads, shells, or aviation bombs were indeed discovered during the Iraq War, these were found to have been manufactured and abandoned much earlier in Saddam Hussein's reign, predating the 1991 Gulf War. These discoveries, therefore, did not corroborate the primary government rationale for the 2003 invasion.

The global outcry against the impending conflict was immense. On February 15, 2003, just a month before the invasion began, worldwide protests against the Iraq War erupted, drawing millions to the streets. A particularly monumental rally in Rome, which gathered an estimated three million people, was even listed by the Guinness Book of Records as the largest anti-war demonstration ever recorded. According to French academic Dominique Reynié, between January 3 and April 12, 2003, a staggering 36 million people across the globe participated in nearly 3,000 protests against the Iraq War, underscoring the profound international dissent.

The Campaign Unfolds: Key Military Operations

The invasion itself was set in motion with a targeted airstrike on the Presidential Palace in Baghdad on March 20, 2003. The very next day, Coalition ground forces launched their incursion into Basra Province from their staging points near the Iraqi-Kuwaiti border. Simultaneously, special forces executed an amphibious assault from the Persian Gulf to swiftly secure Basra and its vital surrounding petroleum fields. Meanwhile, the main invasion army pushed rapidly into southern Iraq, quickly occupying the region and engaging in the fierce Battle of Nasiriyah on March 23. Across the country, massive air strikes relentlessly pounded Iraqi command-and-control centers, throwing the defending army into disarray and effectively preventing any coordinated or sustained resistance.

In a crucial northern operation, on March 26, the 173rd Airborne Brigade was airdropped near the city of Kirkuk. There, they linked up with Kurdish rebel forces, fighting a series of actions against the Iraqi Army to secure the northern oil-rich regions of the country. The main body of Coalition forces continued their remarkably swift drive into the heart of Iraq, encountering surprisingly little concerted resistance. The majority of the Iraqi military was quickly overwhelmed and defeated, culminating in the occupation of Baghdad on April 9. Further operations saw the capture and occupation of Kirkuk on April 10, and the attack on, and subsequent capture of, Tikrit on April 15. As Coalition forces consolidated their occupation of the country, Iraqi President Saddam Hussein and his central leadership vanished into hiding. As declared by President George W. Bush on May 1, this moment formally concluded the intense invasion period, transitioning the conflict into a new phase of military occupation.