An honest look at what an abortion is, and at how many victims it claims, is enough to reveal that nothing outweighs its gravity among the many "life issues." Multiple Church documents have confirmed this insight, repeating over and over that the abortion tragedy demands urgent attention and priority.
While some have tried, shamelessly, to obscure and contradict this teaching, many are quite able to understand and accept it. Yet the truth is even deeper than the statement, "Being wrong on abortion outweighs being right on other issues."
The full truth is, if you are wrong on abortion, you can’t be right on other issues.
To permit abortion, but then to cry out for the right to work, housing, education, health care, and so forth, is to say that these other rights belong to some people but not to all. They obviously do not belong to those who were snuffed out by abortion.
Therefore, these rights cannot be human rights, because you have already said that not all humans have a claim on them. This trivializes those other rights and puts them on an obscure and questionable foundation.
If you permit abortion, then, on what basis do you defend the other rights? Why do we care for the poor? Because they have a right to food, clothing, and shelter. But why do they have a right to those things? Because they have a right to live. Why are we concerned about unemployment? Because people have a right to make a living. Why do they have that right? Because they have a right to live. It all comes back to that foundational right. Abortion is not the only issue, but neither is the foundation of a house the only part of a house. Take it away, however, and see how well you can build the rest.
The reason that being wrong on abortion makes it impossible to be right on other issues is that the heart and soul of every "issue" is precisely the dignity of the human person, whose right to life is not under the dominion of any other person. A person’s dignity comes from the fact that he or she is human, not that someone else decides to grant that right at some point in time. Any human right begins when human life begins; otherwise, it isn’t a human right, but rather some kind of benefit bestowed for another reason.
Now if you can take the right to life away from some humans, as abortion does to the children in the womb, then obviously you can take away from those same humans all their other human rights, because none of those other rights made such a claim upon your respect that you had to let those people live to possess it.
This is why the Pope has said that when the right to life is not protected, cries for other human rights are "false and illusory." When one is wrong on abortion, one cannot be right on anything else.