The distinction in how the world treated the force requests for the Gaza Strip and Libya are worth keeping in mind as the demands from Syrian civilians and armed opponents of the Bashar al-Assad regime for intervention escalate. From Gaza to Somalia, governments and groups make far more requests for humanitarian intervention than you'll hear about in the press. Nearly all of them are summarily rejected as impractical or an inappropriate use of force. Here are just eight of the most recent examples of à la carte requests for military force with humanitarian aims, not one of which was honored or even seriously entertained:

1. In May 2010 (and again in October 2011), the East Africa security bloc Inter Governmental Authority for Development requested that the UN institute a NFZ and naval blockade in Somalia.

2. In February 2011, the Cambodian prime minister appealed to the UN to establish a buffer zone along the border between Cambodia and Thailand to prevent the escalation of skirmishes over the disputed territory near the Preah Vihear Temple.

3. In June 2011, Vice President of South Sudan Riek Machar requested that the UN Security Council establish an international buffer zone between Sudan and South Sudan to prevent military confrontations.

4. At a regional summit in September 2011, Ethiopian Prime Minister Meles Zenawi called on the United Nations to support Somalia's Transitional Federal Government, and the African Union Mission forces helping it, in implementing "corridors of humanitarian assistance" in Somalia.

5. In October 2011, Kenyan and Somali government officials called on "big countries and big organizations" to blockade the seaport of Kismayo, Somalia, which is controlled by al-Shabaab militants.

6. In December 2011, over 20 international nongovernmental organizations (NGOs) petitioned the UN Security Council to establish a NFZ over "Blue Nile, Nuba Mountains/South Kordofan, Darfur, Abyei and also along the border between South and North Sudan," an area slightly smaller than Texas, "for protection of civilians." (About a month earlier, 66 American NGOs had made a similar request.)

7. The same month, Salva Kiir, president of South Sudan, sent a letter to the Obama administration in December 2011 that asked for the United States to impose a NFZ over the border between Sudan and South Sudan.

8. Also in December 2011, the African Union appealed to the UN Security Council to establish a NFZ over and maritime blockades around Somalia. It made similar requests in October 2010, April 2011, and September 2011.

Not one of these received the slightest support from the UN Security Council, NATO, the Obama administration, or any other country able to project military power. It's unlikely that you even heard about it. It's not hard to imagine the three big reasons they were all likely rejected: they were not in anyone's national interest; they required greater resources to achieve a lasting impact than were available; or they were the wrong military mission to achieve the intended military and political objectives.