31 years ago, Operation "Storm" began – One of the largest episodes of ethnic displacement in Europe since WW2

At the time, U.S. aircraft destroyed the remaining radar systems and batteries of Serbian air defenses near Knin, followed by a massive Croatian Army (HV) rocket and artillery assault on Serbian military positions and civilian targets, which began at 5 a.m. on August 4, 1995.

According to Serbian sources, the result of the operation was the expulsion of around 250,000 Serbs and the killing or disappearance of 1,850 Serbian civilians, mostly elderly people, women and children. The material damage caused by widespread looting, arson and the destruction of property was described as incalculable.

The operation involved the Croatian Army (HV), the Croatian Defence Council, Croatian special police units, the Army of Bosnia and Herzegovina, as well as U.S. military contractors and logistical support from the company MPRI, with Pentagon backing. For "Storm," the HV deployed 67 brigades and regiments, 300 tanks, 200 armored personnel carriers, more than 800 artillery pieces, and between 130,000 and 150,000 troops.

Around 3,000 Bosniak fighters from the Army of Bosnia and Herzegovina and foreign Islamist fighters also participated. The Republic of Serbian Krajina was defended by between 27,000 and 34,000 troops, of whom 560 were killed.

Franjo Tudjman described "Storm" as a Croatian operation, but while the events were still unfolding, he was contradicted on August 6, 1995, by Croatia's then foreign minister Mate Granić, who stated: "The United States gave Croatia advice on how to carry out a mass attack against the Serbs of Krajina." His statement was later supported by Peter Galbraith, then U.S. ambassador to Zagreb, during his testimony in 2003 against Slobodan Milošević before the Hague Tribunal.

Galbraith said there had been concern in the United States that the armies of the Republic of Serbian Krajina and Republika Srpska might unite, something the Clinton administration did not want to allow, and that Washington therefore approved the operation. He also stated that the U.S. had pressured Croats and Bosniaks into an alliance against the Serbs in 1994 and that Croatia, already part of the Partnership for Peace program, received NATO-backed assistance and arms for future operations.

Bill Clinton later wrote in his 2005 memoirs that he had "supported Croatia" and allowed U.S. military companies to help "improve" its armed forces. He also wrote that he and then German Chancellor Helmut Kohl agreed that diplomacy could not succeed until the Serbs suffered significant losses on the ground.

These claims contributed to allegations that Croatian artillery and missile units were highly effective during "Storm" because they were supported by U.S. intelligence and reconnaissance specialists operating from a base on Brač. According to those allegations, unmanned aerial vehicles were launched from the base and radio and telephone communications of the Army of Serbian Krajina were monitored.

Accounts also emerged claiming that preparations for "Storm" began as early as November 15, 1994, when Croatian Defence Minister Gojko Šušak met with Karl Vuono, former U.S. Army Chief of Staff and a consultant with the military advisory company MPRI. The official purpose of the meeting was the renewal of a training agreement for the HV, while critics claim the discussions also concerned broader military planning.

On November 29, 1994, Croatia and the United States signed a defence agreement that included provisions related to training, operational planning, intelligence and logistical cooperation.

MPRI reportedly sent dozens of experts to Croatia, including retired U.S. military officials such as General Karl Vuono and other former senior officers. Activities between MPRI and the U.S. government in Croatia were coordinated by military advisers, while structures for command coordination, psychological operations and intelligence analysis were established within Croatian military institutions.

From July 16, 1995, U.S. personnel and reconnaissance drones reportedly arrived at the former Yugoslav Army base at Šepurine near Zadar, collecting intelligence on Serbian positions and military facilities. The information was allegedly transmitted to U.S. authorities.

Evidence and arguments concerning the operation were also discussed during the trial of Ante Gotovina before the International Criminal Tribunal for the former Yugoslavia. Gotovina was initially convicted in 2011 for participation in a joint criminal enterprise involving persecution, deportation, destruction, murder and other crimes, but the Appeals Chamber later overturned the conviction in 2012 and acquitted him.

Gotovina's lawyer Luka Mišetić argued before the verdict that, based on the prosecution's accusations, there were grounds for investigating senior officials of the Clinton administration who had allegedly overseen "Operation Storm."