"U.S. soldiers are killing innocent Muslim men and women. We believe that we have to strike back. We believe in eye for an eye. We don't believe in turning the other cheek...an act, for the sake of God..."
Sound familiar?
If we lived in a tribal society, killing an abortionist would be OK. However, we live in a nation state, where we give up certain rights in exchange for others.
If someone killed your daughter, and you know it, you still cannot go and shoot the SOB. You gave that right up in exchange for the state ensuring that you would receive a fair trial if accused of a crime.
If you are willing to murder an abortionist, you are breaking the contract that privides you protection from others.
Um how about: for the same reason killing babies is wrong?