As we celebrate Black History Month and prepare to celebrate Abraham Lincoln’s 206th birthday, controversies over civil rights abound—from the Academy’s snub of Selma to the ongoing fights over Ferguson and Staten Island to last month’s Supreme Court argument over the future of the Fair Housing Act. Given these controversies, it’s fitting that our nation is also approaching an important set of constitutional anniversaries—anniversaries that remind us of both the progress that we’ve already made as a nation and the constitutional baselines against which today’s controversies ought to be judged.

A century and a half ago, our nation reached an important turning point. President Lincoln had secured reelection, and Ulysses S. Grant was on the march toward Appomattox. With the Union victory within reach, the debate in the North pivoted to how President Lincoln, the Union Army, and Congress should handle the nation’s transition to peace. While these leaders disagreed over the proper pace and scope of Reconstruction, they had settled on at least one important consequence of the war: the end of slavery. The only real question was how to secure it.

Leading up to Lincoln’s reelection, many Republican leaders criticized the President for offering (at most) lukewarm support for (what is now) the Thirteenth Amendment. However, following his reelection in late 1864, Lincoln began to push aggressively for congressional approval of the Amendment, a period of real-life political drama captured beautifully in Steven Spielberg’s film, Lincoln.

In one of the film’s most powerful scenes, Lincoln discusses the Thirteenth Amendment’s importance with his advisors just before a pivotal House vote. One of them urges the President to “leave the Constitution alone.” Lincoln responds forcefully, “I can’t accomplish a god-damned thing of any human meaning or worth until we cure ourselves of slavery . . . This Amendment is that cure.”

For Lincoln, such an Amendment was critical to settling “the fate” of slavery “for all coming time—not only for the millions now in bondage, but for unborn millions to come.” While Lincoln may have freed a number of slaves with the Emancipation Proclamation, he relied on his war powers to do so and feared that his constitutional authority after the war was quite limited. “Abolishing slavery by constitutional Amendment” would resolve all constitutional difficulties by eliminating slavery outright and providing Congress with clear authority to enforce this new constitutional command.

Congress approved of the 13th Amendment on January 31, 1865. The next day, Lincoln took the unusual step of signing the Amendment before sending it along to the states for ratification, calling it a “King’s cure” for the evil of slavery. February 1, 2015, marked the 150th anniversary of this powerful moment, one that took place a mere two months before Lincoln’s tragic assassination. Importantly, it was also the opening act in a five-year struggle to transform our Constitution and, indeed, our nation.

After the Civil War, President Lincoln and his generation secured the passage of a series of Amendments that many scholars rightly describe as our nation’s “Second Founding.” These Amendments contain some of our Constitution’s most inspiring and important provisions, giving our nation what Lincoln promised at Gettysburg, “a new birth of freedom.”

The 13th Amendment was ratified in December 1865. Just as Lincoln envisioned, it forever banned slavery and forced labor. However, ending slavery wasn’t enough to secure the blessings of liberty for the newly freed slaves.

Shortly after the Civil War, many of the former Confederate States passed laws known as the “Black Codes,” which sharply limited the civil rights of the former slaves, seeking to ensure that plantation owners had a continued supply of cheap and compliant labor even after the abolition of slavery. These laws called for strong constitutional medicine. And, after thoroughly investigating the conditions in the South, Congress provided it, drafting and passing what became the Constitution’s 14th Amendment—arguably, the most important provision added to our Constitution after the Bill of Rights.

Ratified in July 1868, this Amendment enshrined a host of new constitutional guarantees in our nation’s charter. It granted U.S. citizenship to everyone born on American soil. It protected individual rights like free speech from state abuses. And it guaranteed equality to everyone.

At the same time, the Amendment did compromise on one critical front: voting rights. Therefore, the American people needed to ratify a third Amendment to secure political equality for the newly freed slaves and, in turn, complete our nation’s Second Founding. The 15th  Amendment was ratified in February 1870, and, with it, our nation finally prohibited racial discrimination in voting—the first of six Amendments that would help establish the right to vote as the most fundamental of all rights in our constitutional system.

Taken together, the Second Founding Amendments profoundly reshaped America’s Constitution in ways that extended well beyond the abolition of slavery. But in the face of a hostile Supreme Court and an increasingly disinterested white majority, the next century saw these inspiring words buried further and further under a thick curtain of Jim Crow laws, as many Americans—especially African Americans—were denied the cherished rights enshrined in these Amendments for nearly a century.

In 1963, the Second Founding Amendments stood, as Dr. King described them, as promissory notes. It took the prophetic courage of Dr. King and the civil rights movement, the passage of landmark statutes like the Civil Rights Act, the Voting Rights Act, and the Fair Housing Act, and the enforcement of these laws and other constitutional guarantees by federal courts, to restore these Amendments to something approaching their original glory.

Today, new groups—like the LGBT community—continue to lay claim to the Second Founding’s core promises, continuing the push for full equality for all. The Supreme Court should answer the LGBT community’s call for marriage equality this Term.

In 1987, the U.S. Constitution turned 200. To celebrate this important milestone, Congress passed a law establishing a commission tasked with planning a series of events over the course of five years. In 1986, Chief Justice Warren Burger resigned from the Supreme Court to head this commission, Congress provided it with millions of dollars in funding, and the commission itself worked with the Reagan Administration, political leaders, civic organizations, leading scholars, and communities across the nation to ensure a fitting tribute to the Framers’ remarkable achievement. And yet, as our nation is speeding towards the 150th anniversary of the Second Founding, much more must be done to begin planning for an official celebration of this important period of constitutional transformation.

While the American people rightly revere Washington, Madison, and their fellow Framers, it took the heroic efforts of President Lincoln and his generation to create the “more perfect Union” that we live in today. It’s only after the ratification of the Second Founding Amendments that the Constitution begins to emerge fully as the inspiring document that it is today. A century and a half later, this Second Founding deserves a proper celebration.

With racial tension and the meaning of equality again at the forefront of political debates, the time is ripe for a national conversation about the enduring meaning and importance of the Second Founding.