About 20 candidates from 13 countries, including from left, Marine Cpl. Dominic Vincentz, originally from Germany; Air Force Senior Airman Deborah Vives, originally from Mexico; Army Sgt. Kelvin Magana, originally from El Salvador; and Navy Petty Officer 2nd Class Hanlin C. Edwin, originally from Micronesia, become naturalized citizens at a ceremony Tuesday at the Smithsonian National Museum of American History. (Katherine Frey/THE WASHINGTON POST)

The 20 sat in ordinary folding chairs beneath a metallic flag, next to strangers who would soon be their countrymen, waiting to become U.S. citizens — Argentines, Indians and Filipinos, as well as a Jamaican, Chinese, Micronesian, Peruvian, German, Bangladeshi, Colombian, Salvadoran and Mexican.

Ariel Fe, a bluff and bald unpublished writer from Argentina, savors the “sense of freedom, equality, opportunity. The sense of enterprise.”

Kevin D. Wagner, born in Jamaica but raised in the United States, was prompted by his five American nieces and nephews to take the citizenship test.

Nirmal Kaur, an Indian woman still struggling with her English, said: “I heard that this is a very free country. When I come here, I got it, 100 percent I got it. This country is number one, I believe.”

On Flag Day at the Smithsonian’s National Museum of American History, before a crowd of students, family members and journalists, 20 people waited patiently. Dressed in their best clothes, they displayed respect for the step they were about to take, ready to “absolutely and entirely renounce and abjure all allegiance and fidelity to any foreign prince, potentate, state or sovereignty, of whom or which I have heretofore been a subject or citizen.”

The summer tourists flooding into the museum stopped in their tracks, witnessing a living history exhibit.

Rashika and Ajay Joshi of India, accompanied by their 21 / 2-year-old daughter, Isha, spoke of opportunity for her and her brother, a second-grader. Ajay also reflected on the responsibility of becoming a citizen in the second-largest democracy in the world.

Kelvin A. Magana, a retired Army sergeant who served in Iraq and South Korea, knows that responsibility. He came to the United States as a child, following his parents, who fled El Salvador during the civil wars of the 1980s and 1990s.

U.S. citizenship, Magana said, means “the freedom to say whatever we feel like and not be afraid of any consequence. . . . It’s very important that people understand the freedom we have here. Now I’m able to treasure the freedom I have because I went through all that.”

Hanlin C. Edwin, a sailor from Micronesia who trained as an electrician, plans “to live here forever.”

Deborah Vives Marquez, a vivacious Air Force senior airman from Mexico, wants to reenlist and make the Air Force her career, which requires citizenship. “I like this country, and I really do like the American way, the way they think — they like to progress, they like to get involved,” she said.

Then the ceremony started, with the bearing of the colors, the singing of “The Star-Spangled Banner” and short speeches. They heard U.S. Citizenship and Immigration Services Director Alejandro Mayorkas describe how raising the flag every morning raises the hopes of people all over the world. They listened to an immigrant from a previous generation,Gerda Weissmann Klein, speak of the moment when she met the U.S. soldier who liberated her from a Nazi work camp and restored her humanity.

Then it was time for the oath of renunciation and allegiance. Members of the armed forces led the Pledge of Allegiance, the flags were removed and flashes from cameras went off again.

Manivardhan R. Billipuram is now no longer from India but from Ashburn. The Joshis are from McLean. And others can say they are from Washington, Prince George’s County, Rockville, Arlington County or, simply, the United States of America.