Iran–Iraq War
The Shatt al-Arab waterway, bordering Iraq and Iran, is crucial to Iraq, because it is its only major outlet to the sea. The waterway is controlled by Iraq and has been a source of tension between the states long before the Iranian revolution. The main reason for tension around this waterway has been its function as a border. Because of this, it has been an issue between the Ottomans and Iran. After the fall of the Ottoman Empire, the waterway was controlled by Iraq. However, in 1969 Shah Reza refused to pay fees for Iranian ships passing the waterway. He also started backing up Kurdish separatists groups in Northern Iraq. To stop the support of Iran to the Kurds, Saddam signed the Algiers agreement in 1975. Iran stopped supporting the Kurds, and the border was placed in the middle of the waterway. One of the reasons, according to Saddam himself, for being pressured to sign this agreement was the military advancement of Iran during the rule of the Shah. Saddam withdrew the agreement several days before invading Iran, in September 1980, drawing upon the importance of the waterway. Before and during the war, Saddam was vocal about the right of Iraq to Shatt al-Arab as well as Khuzestan, the bordering Iranian region that is mainly inhabited by Iranian Arabs.