Josh Marshall explains the Neocon World vision:

We hate the Saudis and the Egyptians and all the rest of the standing Arab governments. But the Iraqi Shi'a were oppressed by Saddam. So they'll like us. So we'll set them up in control of Iraq. You might think that would empower the Iranians. But not really. The mullahs aren't very powerful. And once the Iraqi Shi'a have a good thing going with us. The Iranians are going to want to get in on that too. So you'll see a new government in Tehran. Plus, big parts of northern Saudi Arabia are Shi'a too. And that's where a lot of the oil is. So they'll probably want to break off and set up their own pro-US Shi'a state with tons of oil. So before you know it, we'll have Iraq, Iran, and a big chunk of Saudi Arabia that is friendly to the US and has a ton of oil. And once that happens we can tell the Saudis to f$#% themselves once and for all.