Bombing began on the night of March 24, 1999. The first nights were limited in their targets, and their effectiveness. Wary of casualties, which could turn the Western public against the war, NATO aircraft were ordered not to descend below 15,000 feet above sea level, and Clinton intentionally ruled out the possibility of having US ground forces participate. They were also given explicit rules of engagement that severely limited their ability to perform their tasks. The desire to avoid casualties not only applied to NATO airmen, but to any civilians, Serb or Albanian, on the ground. Thus, in a scenario where civilians were likely to be hurt or killed, the pilot was ordered to turn around and head back to his base. Nevertheless, on March 27^th, Serb Anti-Aircraft (AA) batteries just inside Serbia shot down a US F-117 jet, the most advanced and stealthy plane in the US arsenal. Fortunately for the US and Bill Clinton, the pilot was rescued by a team from Bosnia just six hours later.

NATO’s conditions for a cease-fire were limited, namely an end to the ethnic cleansing in Kosovo, the summary withdrawal of Yugoslav forces, and the entrance of a NATO-led peacekeeping force. When it became clear that the expected few days of bombing would not achieve the desired results, the NAC authorized Phase Two of the bombing, on March 27^h. This allowed a much wider set of targets to be bombed, and more alliance aircraft were called in a result.

When the bombing had first begun on March 24, the Yugoslav forces had stepped up "Operation Horseshoe" to previously unimagined levels. By the end of April, several hundred thousand ethnic Albanians were in unsanitary refugee camps in Albania and Macedonia. Between five and ten thousand Albanians were killed, and Serb paramilitary forces had raped a large, but unknown, number of women. At one point in early May, four thousand people per hour were streaming across the Yugoslav-Albanian border, fleeing the fighting. Reports of these atrocities had the effect of strengthening NATO unity, and worked against the interests of the people committing them.

On April 23-25, NATO celebrated its 50^th anniversary at a convention in Washington DC. British Prime Minister Tony Blair, the greatest proponent of the war, took this opportunity to meet face-to-face with Clinton and push for preparations to commence a ground war. To Clinton, this was unacceptable, since it would probably mean thousands of US casualties. President Jacques Chirac of France also supported Blair. The whole operation was projected to take a total of 175,000 troops, with Blair offering up to 50,000 British soldiers, while Chirac offered a more modest number, probably in the area of 20,000 troops. This would mean the US would have to supply the remaining 100,000 troops, which was no small feat, although it was possible the Italians and Germans might help to defray the total, though at the time they did not make an offer. Still, Clinton said no, even though he was being advised by some that it was a wise choice, tactically and strategically if perhaps not politically.

After this show of unity, Milosevic was forced to realize that NATO would not crack into pieces as he had hoped. His only other hope now lay with Russian intervention. But the Russians, who while opposed to the bombing were not of a mind to prevent it, had in the meantime opened up dialogue with NATO on April 25, to discuss possible diplomatic measures to end the war. Former Russian Prime Minister Viktor Chernomyrdin was assigned to represent Russia in three-way negotiations between Russia, the US, and the European Union.

May proved eventful, with five major events: the accidental NATO bombing of the Chinese Embassy in Belgrade, the continued escalation of NATO air power, the reversal of US policy on ground forces, the diplomatic front, and the indictment of Milosevic and four of his cronies for war crimes by the International War Crimes Tribunal in the Hague.

On May 7^th, a Tomahawk cruise missile launched from a US Navy destroyer in the Adriatic Sea hit and destroyed the Chinese Embassy, in Belgrade. Three Chinese citizens were killed, and twenty-six were injured. The Chinese government and people were infuriated at this attack, but NATO denied it was intentional. NATO maintained that they had been using a CIA map of Belgrade to identify the locations of targets. The intended target was a military installation in the vicinity of the embassy. Unfortunately, the map was six years out of date. The embassy was not marked on the map, and the Serb installation had since been vacated. Thus this tragic and preventable error occurred. In retaliation, the British, American, and Albanian embassies in Beijing were vandalized by up to 40,000 rioters, while Chinese police looked on. NATO and the US profusely apologized to the Chinese government and offered to pay reparations, but their apologies were not heard out for a week, well after the retaliations had taken place. The Chinese government did not offer reparations for the damage to the three Western embassies.

In mid-April, General Clark had requested 400 additional aircraft for the campaign. By early May, these reinforcements were arriving, and on May 6^th Clark asked Clinton for 176 more US aircraft on top of those arriving. This brought up the total amount of NATO planes, both combat and support, to approximately one thousand, the largest air armada assembled in the world since the Gulf War in 1991.

Having hit or attempted to hit all available military targets in Serbia proper, and efforts to hit Serb troops in Kosovo being stymied, NATO now started targeting power relays, television stations, and meeting places of Serb leaders. For several nights in May, large swaths of Serbia were without electricity as electrical relays were shorted out with CBU-94 munitions, which are large payloads of graphite and lead dumped like bombs.

Efforts to hit Serb troops within Kosovo were stymied by bad weather, and dense foliage which Serb heavy units hid under. With most of the Albanian population of Kosovo either internally displaced in the Kosovo mountains or in camps in Macedonia or Albania, NATO had to deal with the very real possibility that winter might fall and the war would be continuing. Balkan winters are particularly harsh, and the people in the refugee camps would probably die from exposure and disease. Naturally, NATO did not want hundreds of thousands of Albanians dying (that was the reason for NATO intervention), so on May 10, the Clinton administration decided to publicly suggest the possibility of US ground troops taking part in an assault.

There were already 25,000 NATO troops in Albania and Macedonia on May 12^th, as a precursor to the anticipated Kosovo Force (KFOR) peacekeeping force. On May 18^th Clinton publicly suggested ground troops, and on May 21^st it was decided that the KFOR-to-be troop levels would be raised to 50,000. Nobody said it, but everyone including Milosevic realized that these projected 50,000 peacekeepers could easily become the vanguard of the NATO invasion force.

Diplomacy continued throughout the month, as Chernomyrdin, Richard Holbrooke of the US, and Finnish President Marrti Ahtisaari (serving a term as President of the EU) worked together to establish a deal that was acceptable to the West and to Russia. By the end of the month, they had done so, and prepared to fly to Belgrade to present the terms to Milosevic.

On May 27^th, Milosevic, his underling, Serbian President Milan Milutinovic, and three other cronies were indicted for war crimes. While these men had not actually been committing the murders, rapes, and expulsions in Kosovo, it was they who drew up the plans for Operation Horseshoe and authorized its implementation. Thus, they were the ones who would have to pay the price. As of summer 2000, Milosevic was still in power and none of these men had seen justice.