The actions of the RUC in the August 1969 riots are perhaps the most contentious issue arising out of the disturbances. Nationalists argue that the RUC acted in a blatantly biased manner, helping loyalists who were assaulting Catholic neighbourhoods. There were also strong suggestions that police knew when loyalist attacks were to happen and seemed to disappear from some Catholic areas shortly before loyalist mobs attacked. This perception discredited the police in the eyes of many nationalists and later allowed the IRA to effectively take over policing in nationalist areas. In his study, "From Civil Rights to Armalites", nationalist author Niall Ó Dochartaigh argues that the actions of the RUC and USC were the key factor in the worsening of the conflict. He wrote:From the outset, the response of the state and its forces of law and order to Catholic mobilisation was an issue capable of arousing far more anger and activism than the issues around which mobilisation had begun. Police behaviour and their interaction with loyalist protesters probably did more to politically mobilise large sections of the Catholic community than did any of the other grievances.