AO1: AO1 In the UK, the party controls the career of an individual MP through selection and deselection; in the USA the state has a greater control over the career of a congressman due to primaries and caucuses AO2: AO2 Party unity is stronger in the UK because for those politicians who wish to retain their seat, loyalty to their party is crucial to selection and for career advancement. In the USA, politicians are more loyal to their state than their party, diminishing party unity AO1: The US has far greater diversity than the UK, meaning the parties there have much broader ideological bases than the UK parties, representing more varied points of view AO2: In representing a larger and more diverse nation, US politicians have a far greater range of views to advance, resulting in a less ideologically coherent party; the smaller size and limited diversity of the UK allows for greater party unity in voting AO1: The US parties have more clearly identified factions than the UK parties, representing different ideological wings of the party AO2: The existence of factions in both countries suggests a lack of unity, however the voting alignment of US party factions is much more reliable than the UK factions AO1: The role of the whips in UK parties is much stronger in ensuring party unification than the whips in US parties. AO2: For MPs who wish to rebel against their party, the role and power of the whips allow for enforced party unity. However, in the USA, the lack of power the whips have allows for members to freely represent their constituency with little fear of repercussion.