My personal belief as to why the Iraq invasion was a good idea:
1. The Global Jihad is best combated through a complete overhaul of government and even society of the MiddleEast. Corrupt, unstable governments with poor developmental policies and no freedom, plus an unresolved crisis and constant foreign invasion is NOT a way to not breed massive discontent. To defeat the global jihad, we should build strong, stable societies.
2. Reform among our current allied states is slow-going, and the global jihad movement was getting stronger faster than our allies could reform to neutralize this. Our Iraq invasion to create a model is our version of the French Revolution, which may lead to a whirlwind of events to create an 1848-style of revolutionary outburst throughout the Middle East and maybe even the whole Muslim world and beyond.
3. Iraq was a state with a dormant WMD program, and thus a threat to the free world. They might not have had WMDs, but all signs to point to Saddam developing WMDs after sanctions ended in order to combat the Iranian threat.
4. Iraq was a potential ally of Al Qaeda. Osama, before making his 1998 declaration of war, went to Saddam. Nothing came of it, but Osama made his choice; if ANYONE was going to help him besides the Taliban, it was going to be Saddam.
5. Saddam was a hostile leader. There is no place for him in a reformed Middle East. In fact, he very likely would have been an opportunistic weasel that would strike an unstable democracy the second he had a chance unless we jumped into protect said state; at the very least, Saddam was sending the wrong message in regard to the Israeli-Palestinian conflict, was willing to cooperate with Syria (a supporter of Hamas and Hezbollah) and in general would have been just as much as a headache as Iran is now.
6. Iraq is a humanitarian crisis now, but it likely would have been one eventually anyways. It’s possible that it’s better to get it done now.
7. Therefore, invade Iraq
1. Iraq had no WMDS!
2. Iraq was an essentially contained state.
3. Even if Iraq did have WMDs, they wouldn’t have been a threat to the United States. We essentially deterred him with our own WMD supply.
4. Saddam would have never allied with Osama. They were ideological enemies, and Osama routinely denounced Saddam.
5. We are inflaming the global jihad
6. We have alienated the Muslim street, making any sort of large reformation difficult to conduct
7. We have strengthened Iran’s hand in the region, once again making reform difficult
8. Therefore, don’t invade Iraq
1. Iraq had a dormant program. They would have reproduced weapons eventually, and inspections likely would have done nothing to slow them down, as we see from Iran and North Korea. A regime totally intent on having WMDs will have WMDs.
2. Iraq was contained largely because Iraq was being bombed daily, deprived of economic supplies, had limited food aid, and had a US force ready to jump his throat. It is unlikely that this status quo could be maintained indefinitely given our political climate, and yet Saddam was STILL a headache for us, and had not yet died and created a Balkans-type situation. Beyond that, Iraq at the beginning of Saddam’s reign had moderate military capacity. Saddam turned it into having the 6th largest army and having a respectable officer corps. Economically, the nation couldn’t handle the burden of wars of sanctions, but we don’t know what Saddam would have been able to do under “normal” circumstances.
3. Proliferation is always negative. It increases the chances of weapons slipping into the hands of terrorists, and the chances of such weapons being used. Not to mention it grants Saddam invulnerability from US attacks if he ever developed his own NUCLEAR stockpile (admittedly difficult, though, as previously stated, not impossible).
4. Osama entirely readjusted his strategies after 1998. An Osama-Saddam partnership would have been entirely possible in 2010 or 2020 had we not intervened. It is now not possible.
5. We are encouraging attacks against us, but the global jihad movement sponsored by Al Qaeda itself is NOT inflamed at all. Al Qaeda proper in Iraq was never all that great, and the affiliated group calling itself Al Qaeda was HEAVILY brutalized, so badly that Zarqawi was filled with despair soon before we killed him. Al Qaeda has no base in Iraq anymore; the Sunnis are beginning to rat them out, and the Shi’a are unlikely to ally with Al Qaeda if they take over, given that Iran would be their protector.
6. Reform has continued through the Iraq War. It is largely a matter of convincing our allied governments to open up and actually be sympathetic to their peoples demands. Many, many, many peoples around the world hate the United States. Very few decision makers are foolish enough to actually challenge the US, and this pattern will hold in the Middle East.
7. Iran is indeed strengthened, and frightened enough that it is attempting to gain nuclear arms while trying to secure regional hegemony. However, we are now in a position to attack Iran, should the need arise, and our efforts have been concentrated on hurting Iran for a long time; Saudi Arabia has been acting as a counterweight somewhat, we have made overtures against Iran in Iraq, Hezbollah was assaulted, Hamas(though I don’t believe Iran had much handwork in Hamas) has been coopted, Iran is unable to get much hard currency(and thus is unable to pay Russia, which depletes it of much political support), and Iran is beginning to experience sanctions. Beyond that, Iran’s sole ally of Syria is flirting with the West, as a result of the West being more open and Syria knowing that Iran has no future.
8. Therefore, the attack is good
It's a lot of broad strokes, and ignores the depreciation of the military that's been going on, but it supports the idea that attacking Iraq was sound policy, if not the specifics of how it was conducted.