The pact that the werewolves and vampires have in Forks (Eclipse) is that the werewolves will allow the vampires to reside in Forks as long as they confine themselves to a set territory and that they take no human prey. As long as they abide by that, they will leave them alone. The weekend before, however, when chasing Victoria, several of the Cullens broke that rule and chased the vampires onto La Push reservation.
