aren't most religious movements political? historically so, definitely, to one degree or another. after all, if it wasn't about power, no-one woud get too excited about foisting it on other people.
Yes, but certainly not to the same degree. It isn't an issue of whether or not we can find religion and politics corrupting each other in all parts of the world with every belief system (of course!), but the capacity of core teachings
themselves to induce such occurances. Islam is pretty much about taking over the world. It's even their center of morality; if it's good for Islam, it's morally good. There is no consistent moral code (like, say, the ten commandments), and this allows for muslims to easily condone things like terrorism and suicide bombings. There's a reason this doesn't regularly happen in the (largely christian) west.