Never take in a dog which you are not prepared to maintain Alpha status against.
Yes, against. Every dog has it's day, meaning every dog will get the urge to vie for the A spot. When it does, you have to be prepared to defend your spot, this means inflicting pain (not neccesarily damage). If you don't think you can face this without flinching, don't get one.
That dog is a huge lawsuit hazard, a Farm-only animal.