You should list it because if you don't most potential employers will want an explanation as to why you were not working during that year and a half. On the application, you can always indicate that you do not want them to call that previous employer and you do not have to list why. (I left a job many years ago w/out notice - on apps I say that I was looking for better advancement opportunities or looking to return to school)
Or... from the standpoint of a previous employer, when someone calls to check on your past employment history, all that employer is allowed (by law) to say is that you worked there from X-month of X-year to Y-month of Y-year, and yes/no if they would hire you again. Legally, if they say any more than that they can get into deep trouble (ie. lawsuits - and future potential employers are not allowed to ask more than that either) because it can prevent you from attaining future gainful employment.
Remember, you are in control of how much info you divulge on previous employment (ie. don't focus on being released from service, but rathar your strong points and why you are suited to the position you are applying for). You can "spin" it as you like. Ethically speaking, don't lie, but don't give damming evidence against yourself either. (and never say anything negative about a past employer during an interview)