The great new film Lincoln, starring famed actor Daniel Day-Lewis and directed by Steven Spielberg, chronicles our 16th president's role in pushing for passage of the 13th Amendment, which Abraham Lincoln called "a king's cure" for the evils of slavery.Passed by Congress at Lincoln's urging and ratified by the states in his memory, the amendment abolished slavery, erasing the stain on our Constitution that had perverted our constitutional ideals of liberty and equality. Just as significant is the role that Lincoln's Gettysburg Address played in presaging the guarantees of liberty and equality in the 14th Amendment, as recounted in great books by Garry Wills, Charles Black and others.At Gettysburg, 149 years ago Monday, in the midst of the Civil War, President Lincoln promised the nation "a new birth of freedom" and called on Americans to defend the Union and vindicate the ideals of the Declaration of Independence. In a speech that was instantly hailed as a "perfect gem," Lincoln looked back to the Founders, who "brought forth" a "new nation, conceived in Liberty and dedicated to the proposition that all men are created equal," and called for a "new birth of freedom" to keep faith with our highest constitutional principles.Tragically, Lincoln would not live to see the "new birth of freedom" he promised at Gettysburg enshrined in the Constitution. Lincoln signed the 13th Amendment upon its passage by Congress in January 1865, but he was murdered four months later, before the 13th, 14th and 15th Amendments became part of the Constitution.These amendments, inspired by the Declaration and Lincoln's promise of a "new birth of freedom," revolutionized our constitutional order. The 13th Amendment abolished slavery, striking out of our polity and Constitution the oppressive system that made a mockery of the Declaration. The 14th Amendment wrote into the Constitution the principles of the Declaration, guaranteeing all Americans substantive fundamental freedoms and making equality a constitutional right. The 15th Amendment extended the promise of the 14th, forbidding racial discrimination in voting and helping to cement in the Constitution Lincoln's vision of a "government of the people, by the people, and for the people." All three gave Congress a leading role in enforcing the constitutional rights they secured.Lincoln's story not only makes for a great film, but it is also essential to understanding the Reconstruction amendments that wrote into the Constitution the "new birth of freedom" Lincoln had promised at Gettysburg.With the Supreme Court the term poised to decide blockbuster cases about affirmative action, the constitutionality of the Voting Rights Act and possibly marriage equality as well, let's hope the justices remember how Lincoln captivated the nation and helped transform the Constitution from a slaveholders' charter to a document that affirms liberty, equality and democracy as our highest constitutional principles.They should all see Lincoln, then reread his "perfect gem" of a speech. Come to think of it, we all should.David H. Gans is civil rights director of the Constitutional Accountability Center.