The war memorial at 12th and U streets here is well off the beaten tourist paths and has no official federal caretaker. So Frank Smith was watering the flowers with his own garden hose on Memorial Day morning when a van with federal license tags pulled up.
He watched a man in a dark suit and a woman in uniform get out of the van and pull a large wreath out of the back. Solemnly, wordlessly, he said, they marched at right angles to the monument. Then they turned and walked straight toward the sculpture of tense young men, looking searchingly over their rifles.
Only after the mysterious couple drove away did Smith check out the card on the wreath.
"They say in this town, the more important you are, the shorter your title," he smiled. The card said simply: "The President."
On a day when people across the USA held parades, hoisted glasses, paused by monuments and headstones to remember those who, as President Obama said, "paid the ultimate price so we might know freedom," the low-key ceremony that took place with Smith as the only witness stood out.
It marked the first time that an American president paid formal respects to the African-American veterans of the Civil War.
"It a good sign for this history of this country," said Smith, a former Washington, D.C., city councilman who helped establish the African American Civil War Memorial. He said he has been trying since 1998 to persuade a president to pay tribute to the 200,000 members of "colored regiments," as they were then known, who helped the Union win.
Obama did not make a personal appearance at the memorial, which is located less than 2 miles north of the White House in a once all-black neighborhood that has now been integrated.
Instead the president followed tradition by laying a wreath at the Tomb of the Unknowns in Arlington National Cemetery. Obama also sent a wreath to the Confederate veterans' memorial at Arlington Cemetery. He did so despite a public letter from a group of professors asking him to break that presidential practice. Among those who signed the letter is 1960s radical William Ayers, a University of Chicago professor. Ayers helped found the radical group the Weather Underground that carried out bombings at the Pentagon and the Capitol.
At the African American Civil War Memorial, reaction to the president's Confederate wreath was mixed. "If the South had won, black people would probably still be slaves," Smith said. "We've got to stop celebrating the things that divide us."
Angela Wilson approved of the president's gesture. "Go Obama," she said. "I think that's a fair decision."
Bobbie Coles, a volunteer at the African American Civil War monument, agreed. "They were soldiers serving a cause," she said of the Confederate war dead. "They should be honored, too."
At Arlington, Obama said the significance of the cemetery's 250,000 marble headstones should trump all petty divisions.
"It reminds us all the meaning of valor; it reminds us all of our own obligations to one another," the president said. "It recounts that most precious aspect of our history, and tells us that we will only rise or fall together."
Across the country, others recognized Memorial Day in ways both solemn and bittersweet.
In Delhi, Mich., the town marked the day with a parade that dates back at least three decades. Local World War II and Korean War veterans led the march to the flag-encircled Veterans Memorial.