Mr. President, today hundreds of thousands of Americans from all walks of life will participate in the 45th annual March for Life.

Why do these citizens march, year after year?

It certainly isn't for their health. Or for the media coverage.

No, these Americans march on behalf of those who cannot.

They march for uniquely vulnerable members of the human family. For the unborn. For those threatened by abortion. And for the countless innocent lives already lost.

These Americans march to protest the legal regime that sustains abortion.

The cornerstone of that crumbling edifice is Roe v. Wade, the 1973 Supreme Court case that invented a so-called "right" to abortion in the Constitution, and in so doing stripped the unborn of their right to life.

The principal effect of Roe on our culture has been to cheapen the value of humanity itself.

Roe has insinuated into the law a poisonous notion, the notion that some human beings may be treated as things. As objects to be discarded when they are inconvenient. We've seen this before in human history.

But an unintended effect of Roe has been to kick-start a movement that has lasted for four-and-a-half decades.

Roe did not resolve the abortion debate-although it tried to. Rather it intensified the debate.

The nation's conscience was not deadened by Roe's euphemisms and evasions; rather it was brought to life.

Like a firebell in the night, Roe awakened a generation of Americans to the injustice of abortion.

Countless thousands of them are marching in Washington, Salt Lake City, and cities across the country today.

But the institution of abortion still has its defenders. Vociferous defenders, even.

Why does this issue arouse such anger and passion?

I argue it is because the pro-life and pro-abortion rights movements offer competing moral visions for our society indeed, competing arguments about human dignity and what it means to be human in the first place.

Both moral visions are as old as the nation. They have appeared in various guises all throughout our history.

But there is a consistent trend in how the clash of visions has played out in every era.

The vision advanced by the pro-life movement has inspired righteous protests. The other vision has been used to rationalize hideous injustices.

The pro-life vision embraces our country's noblest truth. The pro-abortion vision twists it.

Let me explain what I mean.

Our Declaration of Independence contains one of the most succinct and revolutionary statements in human history. 

"We hold these truths to be self-evident, that ALL men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are LIFE, Liberty and the pursuit of Happiness."

We know that the United States has not always acted on this high principle. We have denied life, liberty, and opportunity to our fellow man in countless cruel and unfortunate ways.

But even in the darkest times, patriots and reformers have looked to this passage as a guiding light, because it is the conscience of our nation.

Abraham Lincoln referred to the Declaration constantly in his speeches, calling it the "sheet anchor of American republicanism" and the "Father of all moral principle."

He called the Declaration's statement on human equality the "electric cord" that links patriotic Americans through the ages.

Now that electric cord has reached us. It is a direct line that runs from the Founding Generation to the very heart of the pro-life movement.

The core conviction of the pro-life movement is that "all men are created equal" that all have a right to life.

We believe that every human being has dignity and merits protection simply by virtue of being human.

You will often hear pro-lifers emphasize the human features of unborn children, as well we should.

We point out that the human heart begins to beat as early as 16 days after conception. We point out that the unborn child can yawn, react to pain, and suck her thumb. And we point out that that thumb even has a one-of-a-kind fingerprint.

But we do not mention these characteristics because they are what give unborn children worth. It is not our fingerprints or even our beating hearts that make us people.

Rather, we point to these characteristics because they point in turn to something more fundamental.

They point to the inescapable fact that the unborn child is a human being, just like us. A member of our messy family.

It is that endowment, that shared humanity, that gives us all moral worth.

And so, to summarize the pro-life position, we have only to repeat those five words in the Declaration: "All men are created equal." All are entitled to life.

But to be sure, not everyone shares the belief that all men are created equal.

At various times this belief has been called an "error of the past generation." It has even been called a "self-evident lie!"

Few today would denounce the Declaration of Independence in such terms.

But defenders of abortion still repudiate the Declaration by their actions, and by the arguments they advance to protect legal abortion.

Defenders of abortion no longer dispute that unborn children are living human beings. How could they? Science testifies unequivocally to our shared humanity.

Most sophisticated defenders of abortion do not even dispute that abortion is a violent act.

If you do not believe me on this point, perhaps you will believe Ronald Dworkin, a prominent apologist for the pro-choice position: "Abortion," Dworkin writes, " is deliberately killing a developing human embryo."

He goes on to describe abortion as a "choice for death."

So if abortion defenders do not deny the humanity of the fetus, and if they do not deny that abortion kills the fetus, how then do they defend abortion?

In short, they do it by segregating the human family into two classes: Human beings who are worthy of life-sometimes referred to as "human persons"- and human beings who are unworthy of life- "human non-persons."

According to this view, human beings do not deserve protection on the basis of their humanity alone.

Rather they gain the right to life when they attain certain characteristics-usually some level of cognitive ability or bodily development.

Since the unborn lack these magic personhood qualities, they lack the right to life and may be dismembered in the womb. They are "human non-persons." Or so the argument goes.

There are many problems with this chilling view. It has been rebutted at length by smarter men and women than me.

But for the purposes of today, it is enough to point out the track record of this argument.

Because it just so happens that every time mankind has been artificially divided into classes-into "persons" and "non-persons" based on their race, sex, genetic fitness, or any other attribute-the result has been calamity.

Which leads to a very simple question that has never been satisfactorily answered by abortion's defenders: Why should we believe that this time is any different?

Abortion is a difficult subject matter for so many reasons, but on another level it is quite simple.

Our society has to choose between the two visions of human dignity described above.

Put simply, do we believe that all men are created equal? Or that some are more equal than others?

This simple question deserves a simple response: We must choose the first of those options, and affirm that all human beings are created with dignity.

And we must reject all attempts to separate the human family into higher and lower classes.

Let us see these attempts for what they are: Cruel fictions that cheapen life itself.

Just as there is no such thing as "life unworthy of life," there is no such thing as a "human non-person." There are just people. And we are each fearfully and wonderfully made.

Yes, dignity was ours before we stirred in the womb. It is stamped onto the very fabric of our genome. It is printed onto our soul.

This is the truth so brilliantly proclaimed in our nation's Founding Documents-even as it is denied by our legal system, starting with Roe v. Wade.

But even though the laws of man are against us (for now), the truth is with us. And the truth can erode even the most formidable edifice of lies.

And so, on this forty-fifth anniversary of Roe v. Wade, let us respond to Roe as Frederick Douglass responded to a similar indignity, Dred Scott v. Sandford.

"Happily for the whole human family," Douglass thundered, "their rights have been defined, declared, and decided in a court higher than the Supreme Court."

Those words are as true today as they were when they were spoken.

They call us to continue the winding march for justice-and for life-until the unalienable rights of every human being are respected in our land.

Thank you.