How would one go about negotiating out of a lease due to uncomfortable living standards?

Last semester I moved in with three roommates – one of them being a good friend and two of them being acquaintances. I signed a lease to live here for the year and move out in May. I’ve already given a taste of what one of them is like when I asked my question previously for insight on how to deal with a roommate who neglects animals. The other roommate has a dog living here and engages in pot smoking (both things that break the lease agreement).

This semester, things are a little different. Since I’ve moved back in, I’ve discovered the first day that my friend was moving out and that both of our cars were hit in the parking lot (mind you, my car was hit last semester as well but no one confessed up to it. We caught our other roommate in a lie this time). The other roommate has a power complex and has since taken sides with the other roommate (the one involving the cat situation). My friend is moving out and he has a replacement for his room.

I can’t live another night in this place. However, if I want to move out, my choices are breaking the lease or continuing payment for the remaining months – which is out of the question. I want to approach the landlord and basically say that I’m not exactly comfortable living here because of the pot smoking that goes on, the animals and the fact that my car has been vandalized twice – but I’m also going to state that I don’t want to disclose any names nor get anyone in trouble, I frankly just want out at this point. The landlord seems nice and understanding but I’m not exactly sure how well all of this will go over. I should also note that although things are unfriendly with the other two remaining roommates, I do not want to turn anything into a big legal dispute.

Does anyone have any advice for me – other than to obviously choose my living standards more thoroughly next time?

Before anyone gets on my case for signing a lease with people I didn’t exactly trust; know very well – let’s just say you don’t truly know someone until you live with them. I needed a place at the time and times were desperate. They seemed like reasonable people at the time but their true colors have since shown.