Why does the u. s. presence in iraq pose an ethical dilemma?

The United States has been in Iraq for more than a decade now.

The initial invasion was based on the premise that the country has weapons of mass destruction (WMDs)

However, the weapons were never found and the invasion has led to the deaths of nearly 1 million people in the country.

The focus of the invasion then changed to setting up a democratic government, which happened within a few months.

However, after spending more than a Trillion Dollars, the country remains in a far worse condition than it was before the invasion.

The fact that the invasion happened on a false pretext, resulted in the death of so many and achieved virtually nothing is a huge moral dilemma for the American government.