Hussein Ibish and Pratik Chougule debate the question at the Huffington Post.
Chougule, strikingly, repudiates the doctrine laid out by Reagan advisor Jeane Kirkpatrick in her legendary Commentary article, Dictators and Double-Standards:
The US was virtually alone in responding to the 9/11 attacks with a far-reaching reassessment at the level of grand strategy. The Bush Doctrine recognized the pitfalls of condoning authoritarian governance in exchange for an illusory promise of stability. The nexus of terrorism, rogue regimes, and weapons of mass destruction had to be confronted in a war paradigm - unilaterally and preemptively if necessary. Only the advancement of liberal democracy could serve as an antidote to the noxious strains of Islamism emanating from the region.
No regime embodied the dysfunction of the Middle East like Saddam's Baath Party. The now common critique that Saddam was just one of many dictators is belied by his regime's unique record of aggression: its invasions of Iran and Kuwait, use of WMD, sponsorship of terrorism, and human rights abuses on par with the worst excesses of Hitler, Stalin, and Mao. Saddam remained defiant in the face of the US-led containment regime, which entailed coercive measures that the international community had not imposed on any other regional transgressor. Numerous investigations after the war assessed that Saddam -- the only world leader who openly applauded the 9/11 attacks -- had extensive ties to terrorist groups, and was preparing to reconstitute his WMD programs.
Ibish, for his part, links opposition to the Iraq War among young Arab activists to the Arab Spring:
A further central claim was that the United States could establish a democracy in Iraq that would transform the political culture of the region. Some have even tried to suggest that the "Arab Spring" uprisings against Arab dictatorships are some kind of delayed reaction or long-term impact of the transformation in Iraq. Almost no Arabs believe this, because almost no one in the Arab world looks to Iraq as a success story to be emulated.
Indeed, the main impact of the Iraq war on the crucial turning point in the birth of the "Arab Spring" was the training and experience that many of the most important young activists in the uprising against Hosni Mubarak got during their protests against the Iraq war. So, if there is any correlation between the Iraq war and the democratic uprisings, it has its origins in opposition to the war rather than inspiration from it.
I'm going to send this David's way to see if he has any thoughts. As for me, I was 14 years old when the bombs started falling ten years ago. I count the war as a formative experience for me politically, and to this day think it was a severe mistake. There were no WMDs. Saddam was probably not a near term threat to regional security and stability. Frankly, Ibish's argument about emboldening Iran strikes me as plausible, although I hope to be corrected.
But on the "was it worth it?" question, I can only say yes. The Arab Spring is a scary time for people who sympathize with the residents of the Middle East and Northern Africa. But it's exciting in that fellow human beings are demanding the right to democratic representation. That comes with some pretty nasty hiccups along the way, and the United States must take a vanguard role in demanding these nations respect the basic rights of women.
But removing Saddam was a necessary step in allowing Iraq a shot at its own Spring. There's almost no way the regime would have fallen absent the death of Hussein and his sons. Would a peaceful protest in Baghdad have pushed Saddam from power? Hardly.
So in that sense alone, I'm with Chougle. Yes, it was worth it.