In 1991, military targets in Iraq were bombed by the United States in response to Iraq's invasion of Kuwait. In 2003, the United States invaded Iraq under claims that the country was building weapons of mass destruction and supporting terrorism.
The 1991 invasion of Iraq was part of the Gulf War. With the backing of the United Nations Security Council, the United States bombed military targets inside Iraq in addition to forcing the Iraqi military out of Kuwait.
The 2003 invasion of Iraq happened in the wake of the terrorist attack on the World Trade Center and the ensuing war in Afghanistan. The administration of George W. Bush made claims that Saddam Hussein had revived the country's nuclear and biological weapons program in violation of the Gulf War ceasefire and a United Nations Security Council resolution. United Nations inspectors were unable to find evidence to support this claim, but the Bush administration was able to convince the American people otherwise with a marketing campaign and drum up public support for an invasion. CIA teams and U.S. Army Special Forces first entered Iraq in July of 2002 to prepare for the coming war. The invasion formally began on March 19, 2003.