CAMBRIDGE, Mass.

ON April 9, 2003, Baghdad fell to an American-led coalition. The removal of Saddam Hussein and the toppling of a whole succession of other Arab dictators in 2011 were closely connected — a fact that has been overlooked largely because of the hostility that the Iraq war engendered.

Few of the brave young men and women behind the Arab Spring have been willing to publicly admit the possibility of a link between their revolutions and the end of Mr. Hussein’s bloody reign 10 years ago. These activists have for the most part vigorously denied that their own demands for freedom and democracy, which were organic and homegrown, had anything to do with a war they saw as illegitimate and imperialistic.

To see the connection between the overthrow of Mr. Hussein in 2003 and the overthrow of Hosni Mubarak in 2011, one must go back to 1990, when Iraq’s army marched into Kuwait. The first gulf war — in which an American-led coalition ousted Iraq’s occupying army — enjoyed the support of most Arab governments, but not of their populations. Mr. Hussein’s invasion of Kuwait threatened the order that had kept authoritarian regimes in power for decades and Arab leaders were willing to fight to restore it.

Citizens tend to rally around their leaders when faced with external attacks. But Iraqis didn’t. Millions of Iraqis rose up against Mr. Hussein following the 1991 war, and did what was then unthinkable: they called upon the foreign forces that had been bombing them to help rid them of their own dictator.