With varying degrees of success, authoritarian regimes frequently co-opt their citizens to gather information on and undermine their domestic opposition. According to Martin Dimitrov, communist Bulgaria's ability to suppress dissent was diminished from the 1970s onward because the Western-led international human rights regime forced the government to replace harsher methods it had previously used with a system of rewards for volunteer informants and reprimands for dissidents. The ineffectiveness of these tactics contributed to the regime's eventual collapse. In contrast, Joseph Sassoon explained that Iraq's Ba'th Party—unable to rely upon a superpower for support and steeled by a series of wars—was able to remain in power for thirty-five years in part because it did not relax its efforts at co-optation and repression as the regime matured.