In its long history, there have been landmark, controversial Supreme Court decisions: Plessy v. Ferguson, Bush v. Gore, Shelby v. Holder.

Yet arguably none has divided Americans, defined the parties, and affected the lives of millions of women more than one particular ruling on the 22nd of January 1973: Roe v. Wade and the constitutional right for women to have an abortion.

Since then, those opposed to abortion have campaigned to chip away at that decision, in the hope that one day, when the conditions are right, they can knock down that ruling completely. Is that day almost upon us?

Today, Professor Mary Ziegler, the author of the book “Abortion and the law in America,” talks to me about the history of abortion in the United States, and about recent laws in Texas and Mississippi that could profoundly change the law of the land on this key issue for the first time in nearly 50 years.

Sources: CBS NEWS, MSNBC, ITN.