In his brilliant book, The Sleepwalkers: How Europe Went to War in 1914, Professor Christopher Clark compares Austria-Hungary’s ultimatum to Serbia in July 1914 to NATO’s ultimatum to Serbia (which was then known as Former Republic of Yugoslavia) in March 1999.
On 28 June 1914, the heir to the throne of Austria-Hungary, Archduke Franz-Ferdinand, and his wife were murdered by a Bosnian-Serb nationalist. The Austrian-Hungarian government did not blame Serbia directly for the murder but its investigations unearthed enough evidence for the involvement of various Serbian state agencies and officials in the preparations and training of the assassins and their transport from Belgrade to Sarajevo. The Austrians also feared Serb irredentism, which was propagated by many Serbian newspapers and organisations and had certainly influenced the young terrorists. It was indeed true that de facto all Serbian political and military leaders wanted to “liberate” the South Slavs living in Austria-Hungary and to add the territories of today’s Slovenia, Croatia and Bosnia-Herzegovina to the Serbian state.
Austria-Hungary presented Serbia with an ultimatum on 23 July 1914, which included 10 demands: The first three focused on the suppression of Serb irredentist organisations and of the anti-Austrian propaganda they published. Points 4, 6 and 8 addressed the need to take action against persons implicated in the murder of the Archduke, including compromised military personnel and frontier officials. Point 7 demanded the immediate arrest of two Serbian citizens, which the Austrian believed played a key role in the conspiracy that led to the murder of the Archduke. Point 9 required the Serbian government to explain the hostile behaviour of some high Serbian officials since the murder. Point 10 simply demanded official notification without delay of the actions undertaken to meet the first nine points of the ultimatum. 
The most controversial and most famous points were 5 and 6. Point 5 demanded that Belgrade ‘accept the collaboration in Serbia of organs of the Imperial and Royal Government [of Austria-Hungary] in the suppression of the subversive movement directed against the territorial integrity of the monarchy’. Point 6 stated that ‘organs delegated’ by Austria-Hungary would ‘take part in the investigations’ relating to accessories in the crime. The reason for these two points was obvious: The Austrian-Hungarian leadership did not trust the Serbian authorities to conduct the investigations properly without some form of Austrian supervision and verification. And, according to Professor Clark, nothing that the Serbian government did between the murder and the presentation of the ultimatum gave the Austrians any reason to think otherwise.
Starting in 1998 ethnic Albans in Kosovo, an area belonging to Yugoslavia (Serbia), started to conduct terrorist attacks against Serbian government officials and buildings. They belonged to the Kosovo Liberation Army (KLA), which wanted an independent Kosovo. The Serb military and security forces reacted to the attacks and over the course of the year the violence got worse. In spring 1999 NATO presented both sides with an ultimatum: the so-called Rambouillet Accords. While the KLA eventually accepted the Accords, the Serbian parliament rejected the agreement.
As Professor Clark points out in his book, the Austrian ultimatum was a great deal milder than the ultimatum presented by NATO to Serbia/Yugoslavia in the form of the Rambouillet Accords, which was drawn up in February and March 1999 to force the Serbs into complying with NATO policy in Kosovo. The Accords included the following demand:
NATO personnel shall enjoy, together with their vehicles, vessels, aircraft and equipment free and unrestricted passage and unimpeded access through the Former Republic of Yugoslavia, including associated airspace and territorial waters. This shall include, but not be limited to, the right to bivouac, manoeuvre, billet and utilization of any areas or facilities as required for support, training, and operations.
Clark goes on to say that Henry Kissinger was right when described the Rambouillet Agreement as ‘an excuse to start bombing’. The terms of the Agreement were unacceptable to even the most moderate Serb. The demands of the Austrian ultimatum were almost mild by comparison.
Vienna’s ultimatum was an uncompromising statement of Austria’s position and it drafted in the expectation that the Serbs would most likely not accept it. However, it was not a demand for the unconditional surrender; its terms were focused on the threat posed by Serbian irredentism to the territorial integrity of Austria-Hungary. The Austrian-Hungarian decision-makers believed that Serbian irredentism was a credible threat to the monarchy’s territorial integrity and that Serbian government officials had trained, supplied and helped the terrorists who had killed Archduke Franz Ferdinand, the heir to the throne.
On the other hand, Serbia had done absolutely nothing to any NATO state. Serbia did not threaten any NATO member state’s security or territorial integrity; nor did Serbian government officials, military personnel or civilians support any terrorist attacks against leaders of NATO states. NATO, however, still demanded the de facto unconditional surrender of Serbia. One wonders what the British, French and Russian statesmen, who were so outraged by the Austrian note, would have made of NATO’s ultimatum.
 Clark, Christopher, ‚The Sleepwalkers: How Europe Went to War in 1914‘, 2013, Penguin Books, p. 454
 Ibid., 454-455
 Ibid, p. 455
 Clark, op. cit., pp 456-457
 Ibid., p. 457