Protesters dressed as the Statue of Liberty attend the Women’s March on Washington on Jan. 21 in Washington. (Mario Tama/Getty Images)

For those who live in or will visit Washington, D.C., in the near future, I’d heartily suggest a visit to the Smithsonian’s National Museum of American History, and specifically to the new exhibit “The Nation We Build Together.” It features two separate but interrelated galleries — one on democracy and the other on “Many Voices, One Nation.” Both are particularly timely, eerily so.

On the democracy side, you see the struggle to expand the franchise — from white landowners to poor whites, African Americans (but not in practice until the 20th century) and then women. With setbacks, to be sure, the trend toward greater inclusion and participation is unmistakable. And yes, the fights over voting rights for new citizens, the tension between the promise of the Constitution and state voting laws and the persistent effort to inhibit minority voting seem to be replayed again and again. But — at least until the current president — American democracy has been about widening, not contracting, the electorate. Those attempting to limit the franchise have never succeeded for very long.

The democracy exhibit also presents the messy and contentious means by which Americans express their views — mass marches, lobbying, petitions (from telegrams to emails) — and the unseemly, at times corrupt side of democracy. (Abscam was about 40 years ago, by the way.) Collectively, it’s a needed reminder that democracy does not begin and end with voting, but takes effort, persistence and courage. We cannot be passive observers and expect to keep our liberties and expand our opportunities. Democracy is the antithesis of “I, alone,” as Donald Trump so crudely put it; it’s about everyone. The noise and tumult and dissent don’t stop between elections.

Perhaps even more striking is the “Many Voices” gallery with the provocative subtitle “How did we get to be US?” Sadly, more than one visitor could be heard observing in a stage whisper, “I bet Trump would hate this.” Trump and his followers choose to ignore the story of wave after wave of immigrants and the constantly the changing demographic landscape of cities. Unfortunately, we are not the first generation to witness the tension between exclusionists and newcomers, between the twisted fantasy of a closed society and the necessity of an open one. (Trump’s Muslim ban is nothing new; the Chinese Exclusion Act of 1882 was the first attempt to restrict immigration along racial/ethnic lines.) America was never fixed demographically or ethnically; the composition of America changes in each generation. It can no more be frozen in time in 2017 than it could in 1924 (when immigration exclusion swept the country, shutting the open door that had brought in millions of workers to stoke the Industrial Revolution). What would America be without the Scotch-Irish, the Germans, the Cubans, the Vietnamese and all the rest? The horrific events in Charlottesville, Va., are simply the most recent manifestation of the ugly, racist element that seeks to define America by race, ethnicity and religion.

One is reminded how ahistorical and un-American is the notion that those already here are the “real Americans” who have to keep America from being “lost” to foreigners. Balderdash. America is defined by the process of foreigners becoming real Americans. If we were ever to decide that newcomers contaminate America and dilute its identity, we will have conceded that the American experiment has failed. America has never defined nationhood by race or ethnicity, but rather by devotion to the democratic creed — and its universal appeal to freedom-loving peoples. Tragically, we now have a president who cannot identify and condemn white nationalism as evil. (Instead, he continues to employ as a senior adviser the former chief executive of an online outlet once proclaimed to be “the platform for the alt-right.”)

The president and members of Congress should take a field trip to the new galleries. They might see the full sweep of American history — and realize that the threat to our democracy comes not from “foreigners” (who revere the American dream in ways native-born Americans often do not) but from passivity, cynicism, fear, bigotry and xenophobia — all of which can be exploited by demagogues, anxious to shut up dissenters and pull up the drawbridge.

Seriously, you wonder if the president and his enablers — yes, we’re talking about Stephen Miller and Stephen K. Bannon and the industry of anti-immigrant fear-mongers — have the slightest idea what America is all about. They could use a reminder.