using laurence iannaccone's theory of strict religious clubs (see club good theory), berman argues that successful radical religious groups, such as hamas, hezbollah, lashkar-e-taiba, mahdi army and the taliban, excel at providing social services to their members, while simultaneously filtering out "free riders"; berman calls these movements "some of the most accomplished rebels of modern times." he further argues that the success of groups such as hamas and al-qaeda are more due to their organizational structures than their theology. by way of counter example he examines the case of the militant jewish organisation gush emunim underground, which ultimately over-reached its ability to sustain a group without defections, by carrying out attacks on civilians while neglecting to induce the necessary loyalty in its members and political base through various welfare measures. (previous low-level violent vigilante activity, argues berman, had been treated as a public good by gush emunim settlers.)