The argument of the article: The tensions between Islam's two major traditions are rooted more in current geopolitics than in differences of faith, says Fred Halliday.
from open Democracy:
The conflict now besetting the middle east is, like all major international conflicts, multidimensional. It involves not just one major axis of violence (Israel/Arabs, United States/terrorism, west/Iran) but several overlapping conflicts that draw states and armed movements into their arena. The major concern of strategists and analysts remains the polarisation between the US and its foes in Iraq and, increasingly, in Iran. But there is another important, ominous, conflict accompanying these that has little to do with the machinations of Washington or Israel, and is less likely to be contained by political compromise: the spread, in a way radically new for the middle east, of direct conflict between Sunni and Shi'a Muslims.
http://www.opendemocracy.net/articles/ViewPopUpArticle.jsp?id=6&articleId=4334