President Barack Obama waves as he walks on stage with first lady Michelle Obama and daughters Malia and Sasha at his election night party Wednesday, Nov. 7, 2012, in Chicago. Obama defeated Republican challenger former Massachusetts Gov. Mitt Romney. (AP Photo/Carolyn Kaster)

President-elect Barack Obama and his wife Michelle Obama, arrive at "We Are One: Opening Inaugural Celebration at the Lincoln Memorial" Sunday, Jan. 18, 2009, in Washington. (AP Photo/Alex Brandon)

Vice President Joe Biden and House Speaker Nancy Pelosi talk behind President Barack Obama during his address to a joint session of Congress in the House Chamber of the Capitol in Washington, Tuesday, Feb. 24, 2009. (AP Photo/Pablo Martinez Monsivais, Pool)

President Barack Obama touches names of the 9/11 victims as he visits the North Memorial Pond at the National Sept. 11th Memorial ceremony Sunday, Sept., 11, 2011 in New York. (AP Photo/Pablo Martinez Monsivais)

Sasha Obama, daughter of President Barack Obama, runs from the South Portico of the White House to greet him as he arrives on the South Lawn of the White House in Washington, Tuesday, Sept. 15, 2009. (AP Photo/Gerald Herbert)

President Barack Obama speaks, as a tear streams down his face, at his final campaign stop on the evening before the 2012 presidential election, Monday, Nov. 5, 2012, in Des Moines, Iowa. (AP Photo/Carolyn Kaster)

Vice President Joe Biden shares a hug with President Barack Obama after Obama eulogized Biden's son, Beau Biden, during his funeral at St. Anthony of Padua R.C. Church in Wilmington, Saturday, June 6, 2015. Over 1,000 mourners were in attendance at St. Anthony of Padua Roman Catholic Church, including Attorney General Loretta Lynch; Sens. Mitch McConnell, R-Ky., and Harry Reid, D-Nev., the majority and minority leaders; and other administration officials and political figures. (William Bretzger/The Wilmington News-Journal via AP, Pool)

President Barack Obama smiles in the rain as he and French President Nicolas Sarkozy attend an event honoring the alliance between the United States and France and their efforts in Libya , Friday, Nov. 4, 2011, at Cannes City Hall, after the G20 Summit in Cannes, France. (AP Photo/Charles Dharapak)

President Barack Obama, waves during the White House Correspondents’ Association dinner in Washington, Saturday, April 30, 2011. (AP Photo/Manuel Balce Ceneta)

President Barack Obama delivers his State of the Union address at the Capitol in Washington, Tuesday, Jan. 25, 2011. (AP Photo/Evan Vucci)

President Barack Obama is almost jerked off his feet as he shows off their new dog Bo, Tuesday, April 14, 2009, a 6-month-old Portuguese water dog with his daughters Malia, left, and Sasha Obama, right, on the South Lawn of the White House in Washington, Tuesday, April 14, 2009. (AP Photo/Ron Edmonds)

President Barack Obama embraces retiring Rep. Gabrielle Giffords, D-Ariz., as members of Congress applaud before his State of the Union address in front of a joint session of Congress Tuesday, Jan. 24, 2012, on Capitol Hill in Washington. (AP Photo/Saul Loeb)

Arizona Gov. Jan Brewer points during an intense conversation with President Barack Obama after he arrived at Phoenix-Mesa Gateway Airport, Wednesday, Jan. 25, 2012, in Mesa, Ariz. Asked moments later what the conversation was about, Brewer, a Republican, said: "He was a little disturbed about my book." Brewer recently published a book, "Scorpions for Breakfast," something of a memoir of her years growing up and defends her signing of Arizona's controversial law cracking down on illegal immigrants, which Obama opposes. Obama was objecting to Brewer's description of a meeting he and Brewer had at the White House, where she described Obama as lecturing her. (AP Photo/Haraz N. Ghanbari)

President Barack Obama delivers remarks on the energy bill, Monday, June 29, 2009, in the Grand Foyer of the White House in Washington. (AP Photo/Pablo Martinez Monsivais)

** RETRANSMISSION FOR ALTERNATE CROP ** President Barack Obama throws out the first pitch to St. Louis Cardinals first baseman Albert Pujols, not pictured, before the MLB All-Star baseball game in St. Louis, Tuesday, July 14, 2009. (AP Photo/Haraz N. Ghanbari)

President Barack Obama, accompanied by first lady Michelle Obama, pumps his fist as they watch the torch parade from the balcony of their hotel in Oslo, Norway, Thursday, Dec. 10, 2009. Earlier, President Obama received the Nobel Peace Prize. (AP Photo/Susan Walsh)

President Barack Obama walks across the South Lawn of the White House in Washington, Monday, Dec. 6, 2010, to board Marine One helicopter as he travels to Winston-Salem, N.C. (AP Photo/Charles Dharapak)

President Barack Obama and first lady Michelle Obama dance at the Commander in Chief Inaugural Ball at the National Building Museum in Washington, Tuesday, Jan. 20, 2009. (AP Photo/Charles Dharapak)

President Barack Obama, left, appears on The Tonight Show with Jay Leno in Burbank, Calif. Thursday, March 19, 2009. (AP Photo/Gerald Herbert)

Barack Obama, left, joined by his wife Michelle, takes the oath of office from Chief Justice John Roberts to become the 44th president of the United States at the U.S. Capitol in Washington, Tuesday, Jan. 20, 2009. (AP Photo/Jae C. Hong)

President Barack Obama and first lady Michelle Obama dance together at the Obama Home States Inaugural Ball in Washington, Tuesday, Jan. 20, 2009. (AP Photo/Charlie Neibergall)

President-elect Barack Obama is welcomed by President George W. Bush for a meeting at the White House in Washington, Wednesday, Jan. 7, 2009, with former presidents, from left, George H.W. Bush, Bill Clinton and Jimmy Carter. (AP Photo/J. Scott Applewhite)

President-elect Barack Obama, left, his wife Michelle Obama, right, and two daughters, Malia, and Sasha, center left, wave to the crowd at the election night rally in Chicago, Tuesday, Nov. 4, 2008. (AP Photo/Jae C. Hong)

First lady Michelle Obama, center, hugs former President George W. Bush, as President Barack Obama and former first lady Laura Bush walk on stage at the dedication ceremony of the Smithsonian Museum of African American History and Culture on the National Mall in Washington, Saturday, Sept. 24, 2016. (AP Photo/Pablo Martinez Monsivais)

President Barack Obama shakes hands with President-elect Donald Trump in the Oval Office of the White House in Washington, Thursday, Nov. 10, 2016. (AP Photo/Pablo Martinez Monsivais)

President Barack Obama uses a little body english to make a putt on the ninth green during his golf match at Mid-Pacific County Club in Kailua, Hawaii, Thursday, Dec. 31, 2009. (AP Photo/Chris Carlson)

President Barack Obama gets a high-five as he greets children outside the Kozy Corner diner in Oak Harbour, Ohio, Thursday, July 5, 2012. Obama is on a two-day bus trip through Ohio and Pennsylvania. (AP Photo/Susan Walsh)

President Barack Obama, accompanied by first lady Michelle Obama, and first dog Bo, reads "Where the Wild things Are" during the annual White House Easter Egg Roll, Monday, April 9, 2012, on the South Lawn of the White House in Washington. (AP Photo/Susan Walsh)

President Barack Obama and first lady Michelle are saluted by soldiers as they arrive at the Fort Stewart Army post, Friday, April 27, 2012, in Fort Stewart, Ga. (AP Photo/David Goldman)

President Barack Obama hugs Democratic Presidential candidate Hillary Clinton after addressing the delegates during the third day session of the Democratic National Convention in Philadelphia, Wednesday, July 27, 2016. (AP Photo/Carolyn Kaster)

President Barack Obama drinks filtered Flint, Mich. water during a briefing on the response and recovery plans of the ongoing water crisis by the unified command group at the Food Bank of Eastern Michigan in Flint, Mich., Wednesday, May 4, 2016. (AP Photo/Carolyn Kaster)

President Barack Obama, right, is picked-up and lifted off the ground by Scott Van Duzer, left, owner of Big Apple Pizza and Pasta Italian Restaurant during an unannounced stop, Sunday, Sept. 9, 2012, in Ft. Pierce, Fla. (AP Photo/Pablo Martinez Monsivais)

President Barack Obama bows as he and first lady Michelle Obama, wearing a ruby colored chiffon and velvet Jason Wu gown, gets ready to dance as singer Jennifer Hudson, right, sings Al Green's "Let's Stay Together" at the Inaugural Ball at the Washington Convention Center during the 57th Presidential Inauguration in Washington, Monday, Jan. 21, 2013. (AP Photo/Charles Dharapak)

President Barack Obama and first lady Michelle Obama make claw hands and monster faces while reading, "Where The Wild Things Are," during White House Easter Egg Roll at the White House in Washington, Monday, March 28, 2016. Thousands of children gathered at the White House for the annual Easter Egg Roll. This year's event features live music, sports courts, cooking stations, storytelling, and Easter egg rolling. (AP Photo/Jacquelyn Martin)

A light shines behind President Barack Obama as he speaks during a campaign event at Bayliss Park, Monday, Aug. 13, 2012, in Council Bluffs, Iowa, during a three day campaign bus tour through Iowa. (AP Photo/Carolyn Kaster)

President Barack Obama wipes away tears from his eyes as he speaks in the East Room of the White House in Washington, Tuesday, Jan. 5, 2016, about steps his administration is taking to reduce gun violence. Also on stage are stakeholders, and individuals whose lives have been impacted by the gun violence. (AP Photo/Carolyn Kaster)

President Barack Obama and first lady Michelle Obama, right, dance the tango with tango dancers during the State Dinner at the Centro Cultural Kirchner, Wednesday, March 23, 2016, in Buenos Aires, Argentina. (AP Photo/Pablo Martinez Monsivais)

President Barack Obama and Vice President Joe Biden order lunch at Taylor Gourmet sandwich shop near the White House in Washington, Friday, Oct. 4, 2013. The president and vice president stepped out of the White House on a surprise and rare off-campus stroll to grab lunch at a neighborhood eatery. (AP Photo/Susan Walsh)

President Barack Obama laughs with Ellen DeGeneres during a commercial break while taping a show segment of the Ellen DeGeneres Show in Burbank, Calif., Thursday, Feb. 11, 2016. (AP Photo/Pablo Martinez Monsivais)

Law enforcement officers salute as President Barack Obama arrives at the 32nd annual National Peace Officers' Memorial Service, Wednesday, May 15, 2013, on Capitol Hill in Washington. (AP Photo/Carolyn Kaster)

First lady Michelle Obama, left, adjusts the tie of President Barack Obama as they await the arrival of Chinese President Xi Jinping and his wife Peng Liyuan for a State Dinner at the White House in Washington, Friday, Sept. 25, 2015. (AP Photo/Steve Helber)

President Barack Obama stands at the podium at left as Mark Barden, the father of Newtown shooting victim Daniel is embraced by Vice President Joe Biden during a news conference in the Rose Garden of the White House, Wednesday, April 17, 2013, in Washington, about measures to reduce gun violence. (AP Photo/Carolyn Kaster)

President Barack Obama is greeted by New Jersey Gov. Chris Christie upon his arrival at Atlantic City International Airport, Wednesday, Oct. 31, 2012, in Atlantic City, NJ. Obama traveled to the region to take an aerial tour of the Atlantic Coast in New Jersey in areas damaged by superstorm Sandy, (AP Photo/Pablo Martinez Monsivais)

Republican presidential nominee Mitt Romney and President Barack Obama shake hands during the first presidential debate at the University of Denver, Wednesday, Oct. 3, 2012, in Denver. (AP Photo/Charlie Neibergall)