Some have suggested that Iraq can never exist as a state unless people identify first as Iraqi citizens, thus providing a point of unity for a population otherwise split by ethnic and religious differences. But citizenship, it seems to me, is incompatible with traditions like certain forms of Islam that conceive of politics and governance as functions of religious law. That is, one's allegiance is always with religion/sect and not a secular state or institutions, which are considered inherently illegitimate or subordinate. How would a political philosopher frame an argument for religious fundamentalists to embrace national citizenship?

There certainly are Muslim political theorists who would agree with what you say, and who insist on subsuming everything under religion, including issues of nationalism and government. Even sport is regarded critically as an institution that can lead people to identify with areligious entities and people. There is nothing uniquely Islamic about such a view, many religions not unnaturally regard our relationship with God as our most important relationship and interpret everything else as linking up with this relationship in some way, if it is to be worth pursuing.

Religious fundamentalists as you describe them do not have to accept such a view. Other aspects of our lives may also be regarded as important, although not perhaps as important as our religious life and all that goes with it. John Locke wanted Roman Catholics in Britain to be denied equal rights with Anglicans since he assumed the former, unlike the latter, would take their orders from the Pope, a foreign potentate. I am old enough to remember in the United States some Americans being disinclined to vote for John F. Kennedy since they thought he would take orders from the Pope. Obviously a religious individual would need to take account of the opinions of the religious authorities, yet whether they would need to subsume all their allegiances to those the authorities support is moot. It does not happen in practice and there is no need why it should occur in theory either.

Read another response by Oliver Leaman
Read another response about Justice