To Paul Wolfowitz, the Iraq war was simply the final stage of the Gulf War, which Bush senior had botched. By 1997, he and a group of like-minded neoconservatives had formed PNAC, a neocon think tank whose primary mission was the Iraq War. You can still see (12/2011) their 1998 letter to Clinton advocating the Iraq war. On 9/11/2001 they found the excuse. Dick Cheney had brought eight fellow neocons into key positions in the Bush administration, and they were ready to go. Bush himself was eager to show up his father, who he felt had squandered his Gufl-War political capital

Cheney’s Iraq-War clique all belonged to PNAC or IASPS.  IASPS advocated regime change to increase Israeli security, while PNAC focused on our Middle East allies but named only Israel. Although the public evidence from these groups indicates that helping Israel was by far the most important reason for the war, Cheney’s oil industry connections and a very explicit statement by Kissinger, as well as common sense, indicate that oil must have also been a central concern.

Reasons the Iraq War was planned before 9 / 11

(It would likely not have happened without 9/11, but the neocons were pushing hard for four years before al Qaeda struck.)

1992:  Wolfowitz, in Defense Department, plans for the Iraq war, pre-emptive strikes and for U.S. to dominate the world. Plan leaked to NY Times and then quashed.

1996:  Report from IASPS, a “Jerusalem-based” lobbying group delivers “Clean Break” report from future Cheney/Rumsfeld staff to Israeli Prime Minister. It advocates Iraq War.

1998:  Newly formed PNAC sends letter from Rumsfeld, Wolfowitz, Perle, Abrams, etc.  to Clinton advocating Iraqi “regime change.” 

Up to 9/11:  Cheney says leaving Saddam in power after Gulf war was a mistake. PNAC begins planning specifics, such as “shock and awe” tactic.