"Women are going to have abortions, regardless, because they're desperate. We don't want to go back to the days of back alley abortions. At least, let's make it so the clinics can be regulated and monitored."
Best response: we should first determine if the act is moral...then decide if it's something we want to make/keep legal.
Take this analogy: there's a barbaric practice in some places of female circumcision. I won't go into the details...but it's not a very nice thing to do to young girls.
If we apply the logic that's being promoted by the "Keep abortion legal because women are going to do it anyway" then we should make female circumcision legal so, at least, the instruments used will be sterile and we can monitor them afterwards for infection. It's a practice, after all, that people are going to continue to do, despite the fact that it's illegal.
Of course, no civilized society is going to provide a safe environment for this savage practice.
And yet...there's still this argument going around for abortions.