President Barack Obama leaves Air Force One after arriving at Andrews Air Force Base following on Wednesday, May 20, 2015. President Obama traveled to New London, CT. to speak at the United States Coast Guard Commencement Ceremony. (Zach Gibson / The New York Times)
A secret service agent stands by as Marine One lifts off at The White House in Washington, D.C. on Tuesday, April 8, 2015. President Obama travelled to Jamaica and Panama from April 8-11. (Zach Gibson / The New York Times)
President Barack Obama signs a bill designating areas in Idaho as part of the National Wilderness Preservation System, at the White House in Washington, Aug. 7, 2015. The bill will protect more than 270,000 acres of land in the Boulder-White Cloud Mountains from development. (Zach Gibson / The New York Times)
President Barack Obama and first lady Michelle Obama sing campfire songs with Girl Scouts during a campout event, part of the Let's Move Outside initiative, on the South Lawn of the White House in Washington, June 30, 2015. (Zach Gibson / The New York Times)
President Barack Obama and Canadian Prime Minister Justin Trudeau walk to a bi-lateral news conference at the White House in Washington, March 10, 2016 (Zach Gibson / The New York Times)
Preident Barack Obama arrives on Marine One at the White House in Washington after a trip to Flint, Mich., May 4, 2016. Obama vowed federal support for the beleaguered residents of Flint and said government officials at all levels should have prevented the water contamination crisis. (Zach Gibson / The New York Times)
Members of the audience are reflected in a buffer panel as US President Barack Obama speaks during the opening ceremony for the Smithsonian National Museum of African American History and Culture September 24, 2016 in Washington, D.C. (Zach Gibson / Agence France-Presse)
President Barack Obama and first lady Michelle Obama read the book "Where the Wild Things Are" to a group of children during the 138th annual White House Easter Egg Roll, in Washington, March 28, 2016. (Zach Gibson / The New York Times)
President Barack Obama leads a meeting of the National Security Council regarding the Islamic State group and Syria, at the State Department in Washington, Feb. 25, 2016. From left: Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff; Secretary of Defense Ashton Carter; Secretary of State John Kerry; Obama; National Security Adviser Susan Rice. (Zach Gibson / The New York Times)
President Barack Obama shakes hands with United Nations Secretary General Ban Ki-moon following a bi-lateral meeting in The Oval Office at The White House in Washington D.C. on Tuesday, August 4, 2015. (Zach Gibson / The New York Times)
Former US President George W. Bush receives a hug from US First Lady Michelle Obama as they attend the opening ceremony for the Smithsonian National Museum of African American History and Culture on September 24, 2016 in Washington, D.C (Zach Gibson / Agence France-Presse)
"Key & Peele" actor Keegan-Michael Key acts as "President Obama's Anger Translator Luther" as the president delivers a speech during The White House Correspondents' Dinner at the Washington Hilton in Washington, D.C. on Saturday, April 25, 2015. (Zach Gibson / The New York Times)
President Barack Obama speaks to entrepreneurs Sanum Jain, Ali Ismail, Yeram Kwon, and Fernando Orta during a Google Portal virtual conversation at Stanford Memorial Auditorium in Stanford, Ca., on Friday, June 24, 2016. (Zach Gibson / The New York Times)
President Barack Obama laughs during a town-hall style meeting at McKinley Senior High School in Baton Rouge, La., Jan. 14, 2016. (Zach Gibson / The New York Times)
President Barack Obama signs the bill H.R. 2 Medicare Access and CHIP Reauthorization Act of 2015 in The Rose Garden at The White House in Washington, D.C. on Thursday, April 16, 2015. (Zach Gibson / The New York Times)
Japanese Prime Minister Shinzo Abe makes a toast to President Barack Obama before a state dinner at The White House in Washington, D.C. on Tuesday, April 28, 2015. (Zach Gibson / The New York Times)
Rainbow colored lights illuminate the White House in honor of the Supreme Court ruling allowing same-sex marriage in all 50 states, in Washington, June 26, 2015. In a long-sought victory for the gay rights movement, the Supreme Court ruled Friday that the Constitution guarantees a nationwide right to same-sex marriage. (Zach Gibson / The New York Times)
President Barack Obama speaks during the Catholic Hospital Association Conference Washington at the Washington Marriott Wardman Park in Washington D.C., on Tuesday, June 9, 2015. (Zach Gibson / The New York Times)
President Barack Obama shakes hands with a graduating Air Force Academy cadet during the U.S. Air Force Academy Commencement Ceremony at the U.S. Air Force Academy in Colorado Springs, Co., on Wednesday, June 1, 2016. (Zach Gibson / The New York Times)
President Barack Obama and Sen. Bernie Sanders of Vermont, a Democratic presidential hopeful, walk to the Oval Office for a meeting, at the White House in Washington, June 9, 2016. The president is trying to negotiate with Sanders about exiting the race for the Democratic nomination without damaging efforts to unite the party. (Zach Gibson / The New York Times)
US President Barack Obama and First Lady Michelle Obama greet Singapore Prime Minister Lee Hsien Loong and his wife, Ho Ching on the North Portico of The White House before a state dinner August 2, 2016 in Washington, District of Columbia. (Zach Gibson / Agence France-Presse)
US President Barack Obama arrives before holding a year-end press conference in the Brady Press Briefing Room of the White House in Washington, DC, December 16, 2016. (Zach Gibson / Agence France-Presse)
President Barack Obama arrives at Joint Base Andrews in Maryland after a trip to Jacksonville, FL on February 26, 2016. (Zach Gibson / The New York Times)