To understand why the Iraq War happened, you have to understand the Neocons.
>Historically speaking, the term "neoconservative" refers to those who made the ideological journey from the anti-Stalinist left to the camp of American conservatism during the 1960s and 1970s.[4] The movement had its intellectual roots in the Jewish monthly review magazine Commentary, edited by Norman Podhoretz and published by the American Jewish Committeehttps://en.wikipedia.org/wiki/NeoconservatismThis was basically a group of Marxist jews who saw what was happening in Israel, and decided their nation was more important than their ideology. Their fundamental purpose was to use the Republican Party to accomplish their ethnic interests in the Middle East. They made something of a devil's bargain with the Republican Party: We will give you media, financial, and intellectual support. In return, you do our bidding overseas.
They supported corporate Republican candidates such as the Bush family, who were basically in their pocket.
All of a sudden you saw the Republicans become the "war party" when it had historically been the opposite. All throughout the 90's neoconservatives created all sorts of think tanks, institutes, and magazines to promote war overseas. Neocons were very left wing on other issues, for example they wanted open borders and amnesty, weren't a fan of gun rights, and were totally fine with huge government spending programs.
By the late 90's, neoconservative think-tanks (in particular PNAC) had drawn up invasion plans for every single middle Eastern country, and were lobbying for war. They wanted Iraq, Syria, Lebanon, Libya, and the big prize Iran. In fact in the PNAC papers they specifically call for a "pearl harbor style event" to kick Americans into action to fight Israel's wars.
George Bush was narrowly elected in 2000, and filled his administration with neocons, and the Defense Department.
Conveniently 9 months later, there was a major terrorist attack on US soil that gave the them the excuse for all the wars they had been lusting after for a decade.
Thus the US invaded Iraq based on lies about WMDs
