The average person who identifies himself or herself as "pro-life" believes that self-description works because he or she believes in the sanctity of life and that life begins at conception. Thus, abortion is murder, because it takes away life.
But if, as pro-lifers claim, it is the sanctity of life they are focused upon, that would mean, they want to make sure as few abortions happen as possible - because that would mean that the life that begins at conception would be snuffed out the least often.
In which case - studies have proven that when abortion is legalized, fewer abortions happen, period. Why? Because when someone goes to have an abortion, there is less fear, there are counselors, there are options. There isn't fear. Fear is what causes death. It's what causes abortion, even - someone is scared about being pregnant, for a variety of reasons.
For the sake of argument, let's look at this in terms of math, something that people consider fairly objective. Even the flat earth society uses math. Yes, that exists. No, I'm not going to give them the compliment of a link.
Legalized abortions = fewer abortions.
Fewer abortions = less death.
Less death = pro-life.
We can also apply this argument to another argument about life: gun control. WHAT?! We, the pro-choice, were totally willing to hear to purple hippo out until you implied you might oppose that! But yes. Not that we've actually enacted any significant gun control legislation since the racism-motivated and NRA-backed Brady Bill of Reaganomics, but every time we even talk about the idea of additional gun control legislation, people - gasp! - buy more guns. And hoard them. And become more and more afraid of someone trying to come to their houses and take their damned guns.
And what does fear cause? As with making abortion illegal: more death.
I live in a rural hunting state. Now, most advocates of strict gun control laws that I know are still pro-hunting, responsibly, but it doesn't come out that way to the general working class. All we hear is "the government wants to take your guns."
I say this as someone who doesn't own a gun.
I have also never had an abortion.
The thing is, I have compassion for both. Why? Because I have never experienced the fear that leads to either. I'm a purple hippo. I'm scared of absolutely jack shit.