Four years is a long time when it's a half or a third of your life, and so TV viewers who hadn't seen the Obama girls much since 2008 might have been truly startled at just how much they'd grown when they appeared onstage with their father Thursday night.
After all, Malia Obama, now 14, who started (gasp!) high school this week, was just about as tall as her already tall parents.
Relaxed and composed, in a French blue sleeveless dress, Malia laughed with her father onstage after his remarks, and earlier sat and applauded with her mom and her sister, Sasha, dressed in a black-and-white checked frock. (Now 11, Sasha hardly fits in her parents' laps anymore, and even resists a cuddle, the couple ruefully told People in an interview last month.)
There was one sign, though, that the girls were still kids: "Yes, you do have to go to school in the morning," their dad warned them at the beginning of his speech.
What struck one former White House aide was the ease and comfort with which the girls were inhabiting their public roles.
"Their smiles were genuine and huge tonight," said Anita McBride, a former chief of staff to Laura Bush, as well as an assistant to her husband. "There was no awkwardness. They clearly have adjusted to their life in the public eye." McBride said she was also stunned by how poised and grownup the girls looked.
One reason Thursday's scene was so striking is that the American public doesn't see the daughters regularly, especially on TV. "There hasn't been a steady stream of images to relate to," says Sandra Sobieraj, a correspondent for People who covers the first family.
So for many, the most familiar images are from four years ago. At the 2008 convention in Denver, Sasha, then 7, fidgeted in her purple children's dress, little white barrettes on either side of her head.
"Daddy, what city are you in?" she called out in a high-pitched voice as her dad appeared on a huge video screen the night of Michelle Obama's speech. "I love you, Daddy!" called out Malia, 10, looking a bit older in a two-toned dress with straps.
Then came election night in Chicago. There was Sasha in a black party dress, bounding gleefully up into her father's arms, planting a big kiss on his cheek — a reminder that young children were about to live in the White House for the first time since Chelsea Clinton, Amy Carter, and before them, the younger Kennedy kids, Caroline and John.
And of course there was the inauguration. Who could resist the sight of Malia, in a periwinkle-blue coat and fluffy black scarf, snapping pictures from her enviable perch on the inaugural podium?
Just the night before, she and Sasha, whose inaugural outfit was a light pink coat, had danced onstage with the Jonas Brothers — a perfect example of how, as much as her parents vowed to keep their lives as normal as possible, the girls were truly celebrities from Day One.
For the president and first lady, protecting their privacy was an evolving skill. Candidate Obama quickly regretted, for example, an all-family interview granted to the TV show "Access Hollywood."
Once the family arrived at the White House, strict arrangements were in place. The news media traditionally respects the privacy of a president's young children and doesn't photograph or report on them unless they are in a public setting with their parents.
Yet the couple constantly talks about their kids. At times the president has embarrassed them, as when he told an audience that Malia once got a 73 on a science test. (He later apologized.)
Two years ago, when Malia first went to summer camp, the White House discouraged mention of it in the media, even though Obama mentioned it in interviews. And recently he revealed the state where both daughters had just spent a month at camp — New Hampshire.
"They just love talking about their girls," says Sobieraj. "They get genuine joy from them, and so they talk about it. To a degree that makes the staff uncomfortable, because the line is shifting."
Other White House kids have led less public lives, perhaps a function of the times. Jackie Kennedy was so concerned about keeping her kids out of view that she organized kindergarten for Caroline inside the White House, writes Doug Wead, an expert on presidential offspring, in "All the President's Children." (She was out of town when her husband allowed those famous photos of Caroline and John in the Oval Office to be taken, Wead writes.)
And Bill and Hillary Rodham Clinton were extremely protective of Chelsea, who entered the White House at an awkward stage. Her parents were furious when Mike Myers referred to their daughter in an insulting way on "Saturday Night Live"; the comic later apologized.
Whereas many White House children through history seem to suffer some sort of embarrassment or scandal, the Obama girls have had none.
"Compared to other White House families, this is clearly the most functional," says Wead, who chronicles a host of misfortunes of past White House kids in his book. (He's now working on a book about White House siblings.) "This has been one of the most successful stories."
McBride, who now directs programming on the history of first ladies at American University, says that no matter your politics, it's comforting to see a happy first family.
"Whether you support this president or not, you want to know that it's healthy and grounding and going well at home," she says. "They clearly are a family that's got it together."
The Obamas certainly relish spending time with their kids. The first family is well known to have dinner together in the White House most nights; Michelle Obama in her convention speech evoked the image of the family "strategizing about middle-school friendships."
That will likely help the president avoid some of the guilt that, Wead says, has afflicted some presidents of the past who spent little time with their offspring — like that which he says overcame Ulysses S.
Grant on the occasion of his daughter's White House wedding. She left on her honeymoon, and Wead says the president then collapsed on her bed and wept.
"He had been so busy as president that he felt he had missed her life," Wead says. "It all had happened too fast for him."Suggest a correction