The liberals don't believe unborn children are even human beings. So this argument would be lost on them. To have an impact on liberals, you would have to tackle the argument much earlier in the equation: by showing them that a human being is a human being regardless of whether it's inside or outside the womb. But if you argue them this way, be prepared for their precious "science" to get in the way (the same science that tells us masks work and that the earth's temperature is getting warmer while it's actually getting cooler).