Why was the us invasion of iraq controversial?

The invasion of Iraq, which occurred between March 20 and May 1, 2003, was carried out by a coalition of countries, led by the United States along with the United Kingdom, Australia and Poland. Other countries were involved in the occupation phase. The invasion marked the beginning of the war in Iraq.

According to the president of the United States, George W. Bush, the reasons for the invasion were "to disarm Iraq of weapons of mass destruction (WMD) -which never came to be, nor was its existence demonstrated- to end the ( supposed) support provided by Saddam Hussein to terrorism, and achieve the "freedom" of the Iraqi people. The main detractors of the war point to these reasons as excuses to carry out the invasion, motivated by economic and political interests ».

The invasion of Iraq caused a political fracture between the great powers, which were divided between those who actively opposed the invasion, such as France, Belgium, Germany, Russia, China (as well as other countries that showed a passive opposition), and those that did publicly support the United States, as was the case in the United Kingdom, Spain, Poland, Portugal and other nations that made up the coalition. The invasion (and consequently the war) also caused the first global civic demonstration in history against a conflict.

well we know that it was fought between america and the united kingdom based on that i assume people consider the second war of independence because brtiain and england (uk)   the uk is made up of england and i assume thats why it was considered that