Was it justified?
The justification most people use is that Iraq was believed (without actual evidence) of having nuclear weapons, and the fact the government was run by an evil dictator.
However, there were no nuclear weapons and nor had they the capability to launch them at the US. The war brought Al-Qaeda into the country and created a civil war between the the two main religions (granted, that was more or less unpredictable).
Still, you can't go to war over a baseless threat. There simply was no evidence Iraq had any nuclear weapons other than Saddam Hussein's threats.
And of course evil dictators must always be brought down, but not by a full blown war. There are many other countries standing right now that have evil dictators, but you solve the issue through revolutions like the Arab Spring. If the people want it, then help them, but you can't force it onto them.
What's your opinion on the Iraq War?
EDIT: I forgot to mention that this war paid on credit - one of the most unintelligent decisions ever made in US history since Hoover's inaction during the Great Depression.
Let's see:
4,500 American soldiers dead, unknown number of American contractors
30,000 American soldiers with missing limbs, brain damage, etc
100,000 to 1 million Iraqi dead
850 billion USD on the credit card, plus interest that will take us well over 1 trillion
Iraq's closest ally? Now it's Iran. They both have Shiite governments now (before Saddam was secular with ties to Sunni)
No WMD
No nuclear programs
No links to terrorism, let alone 9/11
distracted us from catching Bin Laden, which Obama eventually refocused on
Um, no, it was not worth it, and Bush and his neo con gang should be held on charges of war crimes. It was a total unlawful invasion based on cooked up phony intelligence.