Interesting. I'd say that christianism is similar in that it's increasingly defining itself by what it's against than what it's for.Good older article about Muslim vs Islam vs Islamism. With all this talk about Islamophobia on here this seems to explain why i think a lot people are considered islamophobes when really they are just islamismophobes.
http://www.washingtoninstitute.org/policy-analysis/view/muslims-vs.-islamists
While Islam is the faith of 1.4 billion people, Islamism is not a form of the Muslim faith or an expression of Muslim piety. Rather, it is a political ideology that strives to derive legitimacy from Islam. Islam and Islamism are not synonymous, and there is even a tension between the two, exemplified by the case of this Nigerian Muslim father turning in his Islamist son to the authorities.
So if Islam is a faith, then what is Islamism? It can be best described as an "anti-" ideology, in the sense that it defines itself only in opposition to things. That is, Islamism stands not for but against.
Of course that a silly distinction because someone who is anti-gay marriage will claim they are pro-family values.