Many things would change during the years, but the government still kept their focus on the oil.
Under the 1975 Algiers Agreement, Iraq ceded 518 km2 of oil-rich borderlands along the Shatt al-Arab in exchange for an Iranian agreement to stop supporting Kurdish rebels in Iraq. But after the fall of Muhammad Reza Shah Pahlevi which resulted in a weak Iranian military, Iraq decided to reclaim the Shatt al Arab. By 1979, however, Saddam Hussein had clawed his way to the top of the ruling junta of Iraq and took advantage of the chaos unleashed by the recent Iranian Revolution to shift the disputed border back in Iraq's favor, with the excuse being that the predominantly Arab population of this region would prefer being part of the predominantly Arab state of Iraq. His armies crossed into Iran in September, 1980. This began the crucial war called the Iran-Iraq War. Hussein wanted to create a super power with Iraq and with a successful invasion of Iran, he could very well reach that goal. Iraq also hoped to seize an Iranian section called Khuzestan, an area known for it's oil fields. A more important issue than geography was religion. Both nations were Muslim, with the leaders from Iran mainly from the Shiite branch and the leaders of Iraq from the Sunni. Before the Iranian revolution, the distinction between the countries was less religious than ideological. The ruling Ba'ath Party in Iraq was socialist and pro-Soviet, whereas the Iranian shah was anti-socialist and pro-Western. The Iraqi leadership became more of an issue after the Iranian revolution, when Ayatollah Khomeini, who had spent part of his exile in Iraq, encourages colleagues to overthrow Saddam Hussein. Khomeini decided on this because he thought Hussein government was anti-Islamic. But Iran was the weakest out of the two. With the revolution coming to an end, it's armies were weak and weary, Khomeini was trying to establish a government, and Marxist rebels were still attacking the religious fundamentalists in the region.