General Roméo Dallaire was the Force Commander of the United Nations Assistance Mission in Rwanda (UNAMIR) in 1994. In January 1994, the Canadian general's mission received information from a Hutu informant about Hutu extremists stockpiling arms in preparation for mass killings. Gen. Dallaire informed UN headquarters that he planned to raid the arms caches and break up the genocide planning. UN headquarters overturned his plans. He repeated his request the next month. Again, he was turned down. By April, Rwanda was in crisis. Eventually 850,000 would die, with millions of people displaced and thousands raped and subjected to other atrocities.*
Gen. Dallaire has published a piece in the Washington Post arguing that the international community is making the same mistake in Iraq. In particular, he is deeply concerned about the role played by children in this crisis. The record demonstrates that we should have listened to Gen. Dallaire in 1994. I'd argue it's well worth listening to him now.
* Information taken from Bruce W. Jentleson, American Foreign Policy, 5th ed. (New York: W. W. Norton, 2014), 574-575.