"But we acted pre-emptively in Kosovo in 1999 to stop Milosevic from doing what he was doing and increasingly doing the ethnic cleansing in a systematic way"

Lord Robertson's quote is describing the NATO intervention in Kosovo in 1999. This intervention was an action to the actions of Yugoslav President Slobodan Milosevic, who had been carrying out a project of ethnic cleansing against the Albanian population in Kosovo. The NATO intervention was a pre-emptive action, taken to prevent Milosevic from continuing his project of ethnic cleansing. The intervention achieved success in stopping Milosevic's actions and restoring peace to the area. The NATO intervention in Kosovo was an example of the international community acting to prevent a humanitarian crisis from taking place. It showed that the worldwide community was willing to take action to secure vulnerable populations from the actions of oppressive routines.