In spring 1991, the United States and allies expelled Iraqi dictator Saddam Hussein's forces from neighboring Kuwait. Iraq's long-oppressed Kurdish minority, encouraged by American radio broadcasts, staged a revolt in northern Iraq. In response, Saddam sent helicopter gunships armed with napalm and chemical weapons to rout the rebels. Hundreds of thousands of Kurdish civilians fled the brutal onslaught, and became trapped on barren hillsides near the Turkish border without food or water. U.S. President George H.W. Bush and his European allies found themselves in an agonizing situation. They were reluctant to remove Saddam from power, but didn't want to see a humanitarian disaster they'd inadvertently instigated [source: Globalsecurity.org].
Instead, they hit upon a solution. In April 1991, the U.N. passed another resolution condemning Hussein's repression of the Kurds and called upon member nations to assist in relief efforts. U.S., British and French air forces moved in and launched a massive supply and rescue operation. The resolution warned Hussein not to interfere with relief efforts, and the allies used that authority to declare what may have been the first no-fly zone in history -- a 19,000-square-mile (49,209-square-kilometer) area north of the 36th parallel. In 1992, a second no-fly zone was imposed south of the 32nd parallel, to protect Shi'ite Muslims who had also rebelled. When Saddam violated the no-fly zones, the coalition forces punished those infractions with force -- either by shooting down Iraqi regime aircraft, or by destroying Iraqi military targets with missiles. The ban continued until the United States invaded Iraq to overthrow Saddam in 2003 [source: BBC News].
The breakup of Yugoslavia in the early 1990s, and the bloodshed that resulted, led NATO forces to impose another U.N.-authorized no-fly zone in 1993 over the breakaway region of Bosnia and Herzegovina. Operation Deny Flight was intended to block Bosnian Serbs, who controlled virtually all the military aircraft in the region, from attacking their Muslim neighbors from the air. The mission later was expanded, and NATO attacked Bosnian Serb anti-aircraft missile installations, artillery and armor in an effort to compel them to stop their aggression [source: Keating, Globalsecurity.org].
After a popular rebellion erupted against Libyan dictator Muammar Gaddafi in the spring of 2011, the U.N. Security Council passed resolution 1973, which banned all flights in Libyan airspace and authorized U.N. members to act individually or as a group to take "all necessary measures" to protect Libyan civilians [source: UN.org]. We'll discuss that resolution on the next page.