history is not a narrative of progress. really i think very many people believe that it is: 'progressives', in short, still working on that 19th-century hegelian-type model. anyway, think about what a believer in progress - setting out the alleged direction of history in 1850, or 1900, or 1950 - would make of a sort of worldwide religious war, unfolding in the 2000s. islam is as much an issue now as in the 13th century. but this is not the 13th century, and occasionally people express their outrage by saying that islamists or whatever it may be want to take us back to some earlier period. all of that is complete confusion, for there is no going forward or backward, for history is not progressive.
it is true that the current outbreak of islamist terrorism and militarism is not exclusivly due to religious factors. it is bound up with world economic structures, the still-unspooling history of colonialism, immigration patterns, and so on. but i take seriously the account of the people performing the murders of journalists or schoolchildren, their own statements about their motivations. i try to do that with everyone, really: take them seriously as giving an account of their own experience. they believe themselves to be doing what their religion demands.
before people even say anything else, they say that only a small aberrant minority of muslims take the truly depraved approach that we are seeing right now in many parts of the world - oh, setting off girlbombs, e.g. ok. right. and yet it is not just a few dozen people in al qaeda cells, is it? there is territorial expansion: syria and iraq, of course, but similar and possibly-allied forces control significant geographical areas in libya, yemen, and nigeria. some groups sport air forces, oil fields, ministries of information, banking systems. sooooo, we might want to worry a little less about the narrative and how people's sensitivities are being affected and a little more about the actual situations on the ground, which really can unfold or are unfolding from spree killings into genocides.
as to any very simple answer to the question of whether islam endorses violence: it is too simple by far. right now the fad is to point out that the koran imposes no penalty for blashpemy, or even for prophet-mocking cartoons. but a religion isn't just a single text or scripture, is it? it's a history of teachings, institutions, actions. if you wanted to describe 'the teachings of the christian religion', you'd have to talk about scripture, but also, say, augustine, aquinas, luther, calvin, etc: christianity here and there as interpreted in that or that cultural context, this or that theological tendency; this strand or that strand and so on. so, it is and it is not a violent religion. certainly, its history is not absolutely pacifist in all cases. what is the history of censorship and prohibition on images and its enforcement in islam, for example? i'm sorry, but a verse from the koran is only a start; there is such a history.