WASHINGTON — His critics insist that he has a messiah complex, but truth be told President Barack Obama seemed more like one of the three old wise men Friday when he made a Christmas-themed visit to an elementary school near the White House.

He groaned while crouching down for a group photograph with second-graders at Long Branch Elementary in Arlington, Va. Though trim, fit, and a mere 49, Obama explained, "I'm kind of old so it's kind of hard for me to get down."

He deglamorized the presidency, telling the kids that sometimes he has to scoop up his dog Bo's "poop" all by himself, and that he doesn't get to enjoy the trappings of the White House with as much abandon as they might because "most of the time I'm working."

Here was Obama's middle-aged-man perspective on why kids shouldn't descend a chimney but why it's okay for Santa: "St. Nicholas is kind of round and he has a lot of padding, so he kind of rolls, so he doesn't get hurt as much."

The president also imparted some fatherly wisdom about what's important in life.

He said the children should think about "how can you guys be nicer to each other." He asked them to think of those less fortunate, including children whose parents can't afford as many presents, or children whose parents are off in the military, fighting the war in Afghanistan.

Long Branch's 514 students can relate better than many. The school serves the military community affiliated with Fort Myer and Arlington National Cemetery. Principal Felicia Russo said perhaps 60 students come from families with a parent in active duty or the reserves or employed in some fashion by the Department of Defense. It's also a diverse school, with students of 25 nationalities.

The pre-Christmas visit to schoolchildren — complete with his readings — is becoming an annual tradition for Obama.

He made a similar stop a year ago at a Boys and Girls Club in northeast Washington when schools were snowed out. On that visit he was in good cheer, having beaten back a Senate filibuster threat hours earlier on his health care overhaul.

This year, with just a dusting of snow on the ground, he had another reason to feel festive. Hours earlier, Congress approved his $858-billion tax cut deal with Republicans.

At Long Branch Elementary, the jolly president read from two books. One was a holiday favorite, "'Twas the Night Before Christmas."

The other was "Of Thee I Sing," a children's book Obama himself wrote for his daughters, Malia and Sasha. The book tells the stories of transformational figures, including Albert Einstein and Jackie Robinson. He signed a copy for the school to keep.

Last year, Obama told children how he and Malia had read all the "Harry Potter" books together. Now Malia's growing up. She turned 12, grew tall, got braces and went off to summer sleep-away camp.

Her younger sister, Sasha, is 9 now. On Friday, Obama high-fived a girl at Long Branch who said her name also is Malia. But he was wistful, telling the youngsters that "I wanted to borrow you guys" because his daughters are getting too old to want him to read aloud to them anymore.

One kid asked how Obama found enough time to write "Of Thee I Sing" while being president. "I actually wrote it a couple of years ago, before I was sworn in," the president said, adding that "because the art is so nice . . . it takes them a long time to make it."

Then the president dashed back to the White House to sign his $858 billion Christmas present into law.

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