U.S. President Barack Obama speaks during the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse near the White House in Washington December 3, 2015. REUTERS/Yuri Gripas TPX IMAGES OF THE DAY

U.S. President Barack Obama hugs Santa Claus as Muppet character Miss Piggy watches during the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse in Washington December 3, 2015. REUTERS/Kevin Lamarque TPX IMAGES OF THE DAY

U.S. President Barack Obama, first lady Michelle Obama (R), their daughters Malia (2nd L) and Sasha, and President Obama's mother-in-law Marian Robinson sing Christmas carols during the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse near the White House in Washington December 3, 2015. REUTERS/Yuri Gripas

U.S. President Barack Obama sings carols with singer Aloe Blacc (L), actress Reese Witherspoon and his daughter Malia (R) during the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse in Washington December 3, 2015. REUTERS/Kevin Lamarque

U.S. President Barack Obama takes to the stage as Santa Claus waves during the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse in Washington December 3, 2015. REUTERS/Kevin Lamarque

U.S. President Barack Obama bows his head in prayer during the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse in Washington December 3, 2015. REUTERS/Kevin Lamarque

Malia (L) and Sasha Obama attend the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse Washington December 3, 2015. REUTERS/Kevin Lamarque

Malia Obama pushes back her hair as she and the Obama family attend the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse Washington December 3, 2015. REUTERS/Kevin Lamarque

U.S. President Barack Obama speaks during the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse near the White House in Washington December 3, 2015. REUTERS/Yuri Gripas

U.S. President Barack Obama hugs a man dressed as Santa Claus as Muppets character Miss Piggy (top L) watches during the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse near the White House in Washington December 3, 2015. REUTERS/Yuri Gripas

U.S. President Barack Obama, flanked by actress Reese Witherspoon and daughter Malia, sings onstage during the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse Washington December 3, 2015. REUTERS/Kevin Lamarque

U.S. President Barack Obama and his daughters Malia (C) and Sasha sing Christmas carols during the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse near the White House in Washington December 3, 2015. REUTERS/Yuri Gripas

U.S. President Barack Obama, first lady Michelle Obama (R), their daughters Malia (C) and Sasha, and President Obama's mother-in-law Marian Robinson sing Christmas carols during the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse near the White House in Washington December 3, 2015. Also pictured are singer Aloe Blacc (L) and actress Reese Witherspoon (2nd L). REUTERS/Yuri Gripas

U.S. President Barack Obama and his family watch the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse Washington December 3, 2015. From left are daughters Maila and Sasha, Marian Robinson and first lady Michelle Obama. REUTERS/Kevin Lamarque

First Lady Michelle Obama and Muppet Miss Piggy read "'Twas the Night Before Christmas" to children during the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse Washington December 3, 2015. REUTERS/Kevin Lamarque TPX IMAGES OF THE DAY

U.S. First Lady Michelle Obama reads "Twas the night before Christmas" to children during the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse near the White House in Washington December 3, 2015. REUTERS/Yuri Gripas

U.S. President Barack Obama, with his family by his side, lights the National Christmas Tree during the Pageant of Peace ceremony on the Ellipse Washington December 3, 2015. At left is actress Reese Witherspoon. REUTERS/Kevin Lamarque

U.S. President Barack Obama waves as he with First lady Michelle Obama (R) and their daughters Sasha (L) and Malia host the National Christmas Tree Lighting and Pageant of Peace ceremony on the Ellipse near the White House in Washington December 3, 2015. REUTERS/Yuri Gripas

Actress Bellamy Young performs at the National Christmas Tree Lighting hosted by U.S. President Barack Obama on the Ellipse in Washington December 3, 2015. REUTERS/Kevin Lamarque

Singer Andra Day performs at the National Christmas Tree Lighting hosted by U.S. President Barack Obama on the Ellipse in Washington December 3, 2015. REUTERS/Kevin Lamarque