At times of dramatic change in a nations history, fear and anxiety can become pervasive and overwhelming. Troubling visions of authoritarianism or chaos, of political persecution, and even civil war disturb our waking thoughts and nightly dreams. It can be emotionally, almost physically, paralyzing.

As Mark Twain allegedly quipped, "history doesnt repeat itself, but it often rhymes." Looking for those historical rhymes can provide perspective at times of disquiet, such as this. This may be particularly true for younger members of our attentive public, who have not lived through, and emerged safely from, some of the dark periods we have experienced as a country.

Americas 241 years of nationhood have been tumultuous. Events have repeatedly challenged the viability of our democracy. Here are just a few.

The Civil War: An estimated 650,000 Americans died during this conflictthe equivalent of 1 in 43 citizens, or more than 7 million souls if it had been fought today.

The Great Depression: Unemployment reached 25 percent (compared to 10 percent at the height of the Great Recession of 20072009). Economic pain gave rise to extremist movements. Communism and fascism both had large followings in the United States, as they did in Europe.

World War II: Unlike any war fought since, this one constituted a truly mortal threat to the future of Western civilization. From 1939 to 1942, the allies suffered repeated defeats at the hands of fascist forces. Nevertheless, except for the shameful internment of Japanese Americans, our democratic institutions continued to function, with regular elections and the rule of law.

1968: The nation witnessed the assassinations of Martin Luther King, Jr., and Robert F. Kennedy. Riots destroyed vast swaths of American cities, where federal troops and armored personnel carriers patrolled the streets.

1970: As anger at the Vietnam War raged, Ohio National Guard members shot and killed four student demonstrators and wounded nine at Kent State University. Strikes shut down many universities around the United States.

197374: A rogue White House burgled the offices of the opposing party. The U.S. president then ordered the crimes cover up. The media, Congress, and the judiciary combined to force his resignation.

Varied as these events were, they show how frequently crises test our democracy, and how resilient it has proven over time. They also show how important it is for defenders of our freedoms to remain vigilant. No civilizationno matter how mighty or seemingly stableis invulnerable. All decline and pass eventually from the scene. Only the values and courage of a free citizenry and its leaders assure that we will continue to confront and rise to the challenges that we will inevitably encounter.

A critical role in preserving our values and our institutions falls to nongovernmental organizations that constitute our civil society. These institutions include our churches, synagogues, and mosques, our universities, and our many charitable and philanthropic organizations. The Commonwealth Fund is one of these. As an endowed philanthropy, The Commonwealth Fund has for 99 years enjoyed the extraordinary privilege of economic independence. Currently, the Fund is dedicated to creating a high performance health system in the United States. In pursuit of that goal, it will continue to provide an independent, nonpartisan, and objective view of our health care system, and of the events and developments that may affect the health and health care of Americans.