When abortion-rights advocates ask why the abortion issue will not just go away, they really mean to ask why, given the stark reality of Roe, the pro-life movement has not dissipated and retreated into the history books.

After addressing a large secular assembly on issues of moral controversy, I turned and faced a woman who urgently wanted to ask me a question: “Why won’t the abortion issue just go away?”

I knew exactly what she was asking. I often meet abortion rights advocates who honestly thought that the national controversy over abortion would simply melt away within a few years of the Roe v. Wade decision legalizing abortion, handed down by the U.S. Supreme Court in 1973.

That was clearly the hope of the Supreme Court majority that signed onto the opinion written by Associate Justice Harry Blackmun. In a note he wrote to himself as he drafted the final opinion and looked to its aftermath, Blackmun revealed a rather optimistic assumption: “It will be an unsettled period for a while.”

Surely, he didn’t mean for that “while” to extend four decades.

Next Tuesday will mark the 40th anniversary of the decision, and the abortion question is anything but settled. Just look at the crowds gathering in Washington next week for the annual March for Life.

In fact, America has been unsettled ever since Roe. Abortion has become a central issue of political conflict, debate and division. If the court had hoped to calm the waters, it failed spectacularly.

As Guido Calabresi, then dean of the Yale Law School, observed, the aftermath of Roe v. Wade produced a “sense of desperate embattlement.” As Calabresi noted, the court’s decision failed to produce a national consensus. Rather, Roe “made it impossible for the opposing views to live with each other.”

Those who thought that the decision of the Supreme Court would settle the issue had reason for that hope. On other controversial questions, the court’s rulings had produced initial furor and outrage, but the nation rather quickly accommodated itself to those decisions. Take integration in public schools.

Not so with abortion.

Why? Professor Lawrence H. Tribe of the Harvard Law School, an ardent defender of abortion rights, recognized that the abortion question presents nothing less than a “clash of absolutes.”

Tribe attempted to propose a means of avoiding “pitting these absolutes against one another.” All such efforts have failed, precisely because the competing claims are indeed absolutes.

When abortion-rights advocates ask why the abortion issue will not just go away, they really mean to ask why, given the stark reality of Roe, the pro-life movement has not dissipated and retreated into the history books.

Here are five reasons why:

First, the radical character of Roe – overthrowing abortion laws in 49 states – galvanized pro-life forces. The judicial imposition of abortion on demand, virtually without restriction until the third trimester, produced both shock and outrage among those who believe that the unborn child has an inalienable right to life.

Within months of Roe, an organized pro-life movement came into shape, looking for any means of limiting and eventually ending the termination of unborn life.

Second, Roe also had the effect, surely unforeseen by the Supreme Court, of bringing millions of evangelical Christians into the fight on behalf of the unborn. Prior to Roe, even many evangelicals believed that abortion was a Roman Catholic issue.

Roe was a legal earthquake that awakened a massive number of evangelicals to the deadly reality of abortion. With remarkable speed, evangelicals soon educated themselves on the issue and then mobilized themselves both politically and culturally.

Third, the death spiral of abortion simply defies adequate calculation. Over a million abortions are performed in America each year. Reports last year indicated that over 40% of all pregnancies in New York end in abortion, a rate that increases to almost 60% of pregnancies among African-American women.

The sheer scale of the death toll sears the pro-life conscience. Young people can now see that millions are missing from their own generation.

Fourth, abortion has proved to be exactly what pro-life activists warned it would be: a deadly threat to human dignity that would target specific populations. Prenatal testing has produced a deadly reality for unborn babies considered less than acceptable by their parents.

The vast majority (90%) of unborn children diagnosed with Down syndrome are now aborted. Sex-selection abortions are legal in the wide-open “right” to abortion declared by the court. Prenatal testing of other characteristics means that parents can now abort a baby that does not meet their specifications and try again.

Fifth, powerful imaging technologies now allow a look inside the womb, a privilege unknown to previous generations. That window has transformed the equation, as millions of parents have seen their unborn children and witnessed the miracle of life.

They have seen the little human form and the actions of the unborn child, sucking its thumb as it nestles within its mother. Millions of siblings have seen the images of their unborn brothers and sisters taped to the refrigerator door.

Those of us who believe that every single unborn child has a right to be born cannot resign from the effort to protect those lives.

The greatest advances made by the pro-life movement have been made among the young, the generation that has known the death toll from Roe v. Wade all their lives. More evidence that the abortion issue will not simply go away.

Nevertheless, Roe v. Wade remains the law of the land and abortion on demand remains a constant. Since Roe more than 55 million unborn Americans have been aborted, and the nation is more concerned about economics than the sanctity of human life. We have much ground to recover, but the only foundation for a recovery of human dignity is an affirmation of the fact that every single human being is made in God’s image and is of sacred worth from the moment of fertilization until natural death.

Until that truth is affirmed, we will see abortion remain the law of the land and human dignity will hang in the balance.

R. Albert Mohler, Jr., serves as president of The Southern Baptist Theological Seminary. This commentary is taken from his blog and is used with his permission.