Beware, there be pontification below. I'm assuming that we've already shed the people who care less about politics.

I've got a better idea for fredster, jbox. I suggest he sits there and waits for you to tell him what you would do about the situation.
Well, that ploy didn't work, so in fairness here's my answer. I'm going to assume that I get to hold the tiller the entire way, instead of being expected simply to fix the jingoist wet dream currently in progress. Here's just a few things I'd love to be "king for a day" to do differently...
1. Take 1 day a week off, not 3.5 days (on average). Read books about the 'evil' governments and how they came into power.
2. Look at what imports the USA cannot live without. Promote work in those areas of research which *eliminate* that dependance in scalable ways. Give the finger to the rest of the world as the USA takes the lead in alternative power generation and conservation, vastly re-enforcing the greenback as foreign imports drop correspondingly. Admit there is such a thing as an environment, and that people should be worried about how they are treating it. Sigh with relief as the middle east ceases to become an economical burden, merely a political one.
3. Order a policy review of all big government contracts. Require an open tender process for all future contracts. Promote legislation that requires all elected officials and senior non-elected officials to provide public documentation describing all corporate ties (including a complete employment record) as well as an investment portfolio summary. This summary must also include anybody with whom they currently have an asset-sharing relationship of more than $1,000 per annum.
4. Stop making corporations stronger. Improve the environmental liability laws. Work with the UN to develop both environmental and human rights standard documentation that then become part of the WTO mandate on globalisation. Promote the removal of trade barriers as a conclusion of human equality, not some magic wand that will supposedly create it. As part of this process launch a public education campaign to teach people the difference between the *price* of something and the *cost* of something. And for goodness sake do something to make it clear that software and genetic patents are wrong.
5. Appreciate human falability, and that if God is truly beyond comprehension, than anyone who claims to know what God wants is obviously lying. Develop dialogues amongst recognised religious and civic leaders. Ask them to submit position papers debating the need for more or less religious motivation in government, including examples from history where those tactics did or did not improve the QoL of their citizens. Retain religous equality until such time as there is only one religion left in america.
9/11
6. Immediately fire those officials directly responsible for the break down in the chain of command from the first message to the final plane hitting. Anyone who needs 'protective custody' gets it, but here in america. No one is going anywhere until we know what the hell just happened.
7. Order all subordinates to participate fully with the investigation process. Don't screw over the investigation committee, refuse to go under oath, and then pretend the public *shouldn't* hold me responsible for this terrible event happening under my watch. Don't censor the report, since anyone who assisted on this attack against america is clearly not "with us".
8. Understand the social, political and economic reasons why this sort of thing happens. If the best excuse I can come up with is "bad guys hate good guys", resign. Don't pretend that the USA didn't train these sorts of bad guys in the first place.
Afganistan Invasion
9. GOLD STAR - half the world didn't even recognise these guys as a legitimate government.
10. Now stay there, with removing/reforming the remaining warlords a key priority of the administration. If democracy is the shining goal of all unavoidable hostilities, use the next four-eight years of reforming Afganistan into a 'western' civilisation to prove to the rest of the world who the 'good guy's really are. Don't start another war until (a) another major attack occurs, or (b) we finish up here; so that I don't have to hold portions of my own military as virtual slaves. Find out if there are places in the military budget that could be re-allocated more efficiently. Don't try to 'own' afganistan in return for your efforts.
Iraq Investigation
11. Immediately sack my so called 'advisors' who attempted to lie to me about Iraq. Flush the nest of those people who participated, including the head of any intelligence agency that forgot they are supposed to work for the public rather than the president. Immediately order another investigation on another huge failure, and order a new study to be released that actually include the "bad-fact" reports previously censured.
12. Apologise to the world at large for letting the lie get so far up my chain of command, and for repeating it to my country. Ask myself again if I am capable of this job.
13. Continue to work with the UN weapon's inspectors in Iraq. Continue to work with the Kurds towards formally creating their own nation. Use that process as the second opportunity to demonstrate to the world that self-governance is our over-riding goal.
14. Define a policy for providing guidance to the administration on what precisely defines a terrorist. Start getting serious against any government which matches that profile, eg. such as permanently cutting 1mil off their annual 'gift basket' each time they kill anyone not carrying a weapon. As an after thought order a review on any 'uncle sam friendly' operations and make sure to cancel any of those currently in violation of that policy as well. Stop transferring prisoners into other countries so they can be 'tortured-by-proxy'.
15. GOLD STAR - use the words "palestinian state" in public. Now do it more often, and lay down the gauntlet for other governments to do the same. Don't veto resolutions in the UN, then get righteous when other members do the same. Use this process as the third opportunity to develop democracies around the world.
So, fire away. And yes, Saddam is (probably) still in power of the Shi'ites. But with three democracies now under her belt I think the odds will be marginally better that more of the global community will pitch in as the USA continues to 'upgrade' each non-democratic country. Most likely, since they went into revolt once before in response to the USA promising to help, if the USA actually started *keeping* that promise, who knows how quickly more populations in the middle east would actually help liberate themselves once word got around that true independance was back on the menu...
And GOLD STAR for getting any number of people to show up for an election in that kind of climate. However, I don't believe it's a good idea to have a yes/no referendum, and would rather see a condorcet style ballot. Our beloved government in OZ managed to scuttle a republic referendum by making it yes/no choice. And my personal opinion is that if they want to split that country into three smaller ones, let them.