On October 15, 1966, President Lyndon B. Johnson signed the National Historic Preservation Act (NHPA) into law, ushering in a new era for historic preservation in the United States. The 50^th anniversary of the NHPA is an occasion to celebrate, and also to ponder the past and the future.

Here’s how President Johnson spoke about the future in 1964—a future that has now become our present:

Many of you will live to see the day, perhaps 50 years from now, when there will be 400 million Americans—four-fifths of them in urban areas. In the remainder of this century urban population will double, city land will double, and we will have to build homes, highways, and facilities equal to all those built since this country was first settled.

As we think about the future of the NHPA, it’s worth taking a look at the broader context in which the Act was passed to consider the full reach of its vision—specifically the expansive aspirations of President Johnson’s Great Society, which sought to improve dramatically the lives of all Americans.

Two key Great Society initiatives relating to historic preservation preceded With Heritage So Rich, the report from the United States Conference of Mayors that remains one of the most evocative and powerful statements for historic preservation and formed the basis for the NHPA. The first was a task force on the Preservation of Natural Beauty, which met on July 31, 1964. The second was Beauty for America, the White House Conference on Natural Beauty, chaired by Laurance Rockefeller, which met in May, 1965. Gordon Gray, Chair of the National Trust at the time, served on the Townscape panel, and the recommendations from the conference included a broad agenda for recognizing and protecting historic places.

In calling the conference, Johnson wrote about the way that beauty—and he included historic districts and landmarks in the concept—can “enlarge man’s imagination and revive his spirit.” This phrase captures the optimistic and progressive context of the Great Society initiatives in which the NHPA was conceived, drafted, proposed, passed by both houses of Congress, and signed into law. Although the idealism of the Great Society has largely been obscured (“burnt away” might be a better term) by the anti-war protests, assassinations, race riots, and distrust of government that followed, the progressive ideas and raw political power behind the Great Society aligned the stars for broad-based federal legislation on historic preservation. Or as Gordon Gray put it, “the moon was right.”

The NHPA, signed into law the same day as the Department of Transportation Act, was part of the legislative program that sought to implement the vision of the Great Society, including the Voting Rights Act of 1965, the Water Quality Act of 1965, the Motor Vehicle Air Pollution Control Act of 1965, the Land and Water Conservation Fund Act of 1965, and the Social Security Act Amendments of 1965 (creating Medicare), among others.

Like these other laws, over the next 50 years, the NHPA made a profound difference in the lives of all Americans. Yet, just as Americans are largely unaware from day-to-day that they breathe clean air as a result of the Clean Air Act, they are also often unaware of the ways in which their lives are better because of the historic places saved by the NHPA.

Two examples illustrate the impact of the Act. Without the NHPA, the heart of the French Quarter in New Orleans could have been forever marred by an elevated highway between Jackson Square and the Mississippi River, something that seems incomprehensible today. In a more recent example from New York City, the Act helped preserve the African Burial Ground, a place now widely thought of as hallowed and “one of the most significant archaeological and historic finds in the United States of the 20th century.”

For 50 years, the NHPA has been working to save places throughout the United States, places that give Americans the “cultural, educational, aesthetic, inspirational, economic, and energy benefits” envisioned in the Act’s preamble. But the NHPA could do more. In listening to many people talk about the future of preservation, I hear impatience about the fact that the National Register of Historic Places doesn’t represent the full diversity of the American people (despite the laudable efforts of the National Park Service); that federal agencies don’t always demonstrate a strong preservation ethic; and that the NHPA doesn’t always capture the places of memory and identity that people care about. The American people want their stories told and the places important to them honored.

The underlying vision out of which the NHPA grew was of an America that is more fair and livable for everyone. Johnson said:

The Great Society rests on abundance and liberty for all. It demands an end to poverty and racial injustice, to which we are totally committed in our time. … The Great Society is a place where every child can find knowledge to enrich his mind and to enlarge his talents. It is a place where leisure is a welcome chance to build and reflect, not a feared cause of boredom and restlessness. It is a place where the city of man serves not only the needs of the body and the demands of commerce but the desire for beauty and the hunger for community.

In every part of that statement, I see a role for older and historic places, from recognizing the stories of all Americans, to using our older assets to foster a strong economy, to appreciating the beauty old places give our communities. But I’m also struck by the way we are still grappling with some of the same issues 50 years later, from racial inequality to the balance between commerce and community—issues present in our preservation work every day.

Regardless of what one thinks of President Johnson, the rhetoric of the Great Society expresses ideas still worth pursuing. I’m inspired by the idea in the NHPA of our historic places as a living part of community life. Yet the question before us today is not how we fulfill that vision from 50 years ago, but what our vision is for NHPA today, in 2016, and in 2066. I hope we will be as expansive and forward-thinking as Gordon Gray and the other visionaries were in 1966. I hope that we will find ways for the NHPA to represent the full diversity of our American story, to capture the places of our identity and memory, and to use our historic places to help make our communities more healthy, equitable and sustainable. May the moon once again be right.