The 2003 Invasion of Iraq by the United States and the “coalition of the willing” had profound effects on Middle Eastern regional politics.
Firstly, it took Iraq out of the region’s power game. Already suffering after decades of war and sanctioning, this invasion and subsequent coup ensured Iraq would, in no time soon, reach the levels of power it once held and be a major player in influencing the region’s happenings. Their longtime opponent, Iran, was therefore able to take advantage of their gap and emerge as a leading regional power without its neighbor challenging it.
Iran, since the 1979 Islamic Revolution, has not been a United States ally. Their emergence as a significant power shifted dynamics in the region. Iran, as a counterforce of U.S. allies and many Sunni-led governments, has since interfered in the politics of competing countries and supported Shi’a groups like Hezbollah. The 2003 invasion and Iran’s power growth has perhaps allowed them more freedom in massively building up arms, and maybe a nuclear program.
Saudi Arabia, on the other hand, has filled the spot of a U.S.-backed power, and has also emerged as a major economic influence. Since Iran has become the main leader of the Shi’a Arab world, Saudi Arabia has filled the same role for the Sunni Arabs. In opposition of Iran, and in peace with the United States, Saudi Arabia has pursued negotiations and peace between Arabs and Israelis. The rise of Saudi Arabia has made the Gulf Region bipolar (with Iran at the other axis) with tense, but relatively non confrontational, relations.
The invasion also demonstrated a shift in U.S. intervention in the region. The Iraq War was in no way sanctioned by the UNSC, was mostly unilateral in nature, and the reasons for it turned out to not be validated. This proved the ability and, above all willingness, of the United States to intervene in the region, even if unpopular. Also, the invasion served as a justification for the U.S. to have constant military presence in the region, and the ensuing power dynamic change has just strengthened this position.
Another significant consequence was the rise of many terrorist groups. The invasion led to much instability, economic downturn and anti-Western sentiment within Iraq, which allowed for different fringe groups to gain power quickly and efficiently. It therefore partly allowed for the emergence of the Islamic State in Iraq, which has continuously exerted influence against not only the U.S., but in non Islamic governments and U.S. allies. This marked a shift towards non-state significance in international politics. These groups are also often supported by other states or regimes, which complicates the relationships between states.
The resulting shift of power in the region after the 2003 invasion allowed for new actors to fill voids and old actors to step up to a relatively unchallenged level. This has created a fractured political system with multiple different fronts, supporters, and ideologies. Not only has this affected the Gulf, but it has also affected the United States, which has ramped up presence in the Gulf and doubled down on existing alliances and agreements. This, in turn, has affected how the U.S. is perceived in the Gulf, especially by non U.S.-allied states, their groups, and their citizens.