AN ARGUMENT FOR ABORTION
P1. If abortion is illegal, unsafe and unregulated abortions will take place
P2. It is not desirable that unsafe and unregulated abortions take place
C. Therefore it is not desirable that abortion is illegal
This argument is similar to the claim that drug use will occur irrespective of the law so it should be legalized to make it safer and regulated. It is not always true that a behavior should be legalized so it can be controlled and regulated, there are many behaviors which are illegal because they are simply immoral.
P2 is true that it is not desirable that abortions take place unsafely and unregulated but legalizing abortion is not the only way to ensure that unsafe abortions do not occur.