The predominant model of dynastic monarchy (Herb, 1999) sees competition within monarchies as a natural and even beneficial element of family rule. While acknowledging the temptations of external coalition building towards building political advantage, it argues that internal cohesion will ultimately prevail due to threat of losing family power and through the mechanism of bandwagoning. This paper revisits this argument by examining the recent history of factional competition in Kuwait and Bahrain. Relative to other Gulf monarchies, these states demonstrate high social mobilization institutionalized in relatively robust legislatures and dynamic civil society organizations. As states, they also have exhibited vulnerabilities, both having been subject to foreign interventions, invited (Saudi National Guard forces in Bahrain in 2011) and uninvited (Iraqi forces in Kuwait in 1990). As such these monarchies reveal weaknesses and represent hard cases for regime stability. These more historically built attributes are further challenged by the temporal realities of 1) complicated successions or power imbalances within the ruling family and 2) the strenuous regional conditions of the Arab Spring. Thus for both temporal and structural reasons, it is reasonable to posit that if cracks were to appear in the model of dynastic monarchy, currently these monarchies would be the ones to show them. I argue that under these conditions, royal factionalism in these states is actually breeding instability rather than security. Royal rivals are extending their reach through domestic coalitions and foreign alliances in ways that are undermining the unity of the state. In Bahrain the ascendance of new royal factions has precipitated dramatic shifts in policies and ideology, exacerbating sectarian relations. Moreover, factional rivals have sought to augment their power through international alliances, inviting proxy battles and weakening the cohesion of the state. In Kuwait youthful contenders to succeed the current Emir have engaged in a no holds barred competition through the parliament, leveraging parliamentary clients to undermine the ministerial power and influence of their rival. This has lessened the effectiveness of both the government and the parliament, and has left the ruling family open to criticism of poor government performance and corruption, strengthening a youth-driven opposition. In reviewing the dynamics of dynastic monarchy in these two hard cases, the paper will strive to extend the implications for the stability of Gulf monarchies with the probability of a future decline in oil revenues and the continued populist demands of the Arab Spring.