First Lady Michelle Obama and President Barack Obama exit Marine One after arriving at The White House after attending the UN General Assembly in New York September 21, 2016 in Washington, DC. / AFP PHOTO / ZACH GIBSONZACH GIBSON/AFP/Getty Images

First Lady Michelle Obama and President Barack Obama exit Marine One after arriving at The White House after attending the UN General Assembly in New York September 21, 2016 in Washington, DC. / AFP PHOTO / ZACH GIBSONZACH GIBSON/AFP/Getty Images

US President Obama returns to the Oval Office after arriving at the White House September 21, 2016 in Washington, DC. / AFP PHOTO / ZACH GIBSONZACH GIBSON/AFP/Getty Images

WASHINGTON, DC - SEPTEMBER 21: Speaker of the House Paul Ryan (R) (R-WI) laughs as Sen. Chuck Schumer (C) (D-NY) and Senate Majority Leader Mitch McConnell drive nails into a piece of lumber at the "First Nail Ceremony" September 21, 2016 outside the U.S. Capitol in Washington, DC. The ceremony marked the official launch of construction on the Inaugural platform where the next President of the United States will take the oath of office on Friday, January 20, 2017. (Photo by Win McNamee/Getty Images) *** BESTPIX ***

WASHINGTON, DC - SEPTEMBER 21: Internal Revenue Service Commissioner John Koskinen (L) says goodbye to House Judiciary Committee members (L-R) Rep. Ken Buck (R-CO), Rep. Mike Bishop (R-MI) and Rep. Trey Gowdy (R-SC) after Koskinen testified for more than three and a half hours in the Rayburn House Office Building on Capitol Hill September 21, 2016 in Washington, DC. Despite the lack of evidence against him, Koskinen is facing impeachment threats from conservatives in the House of Representatives for his role in the destruction of computer backups containing thousands of emails sought by Congress in its investigation of political targeting. (Photo by Chip Somodevilla/Getty Images)

WASHINGTON, DC - SEPTEMBER 21: Internal Revenue Service Commissioner John Koskinen talks to reporters after testifying before the House Judiciary Committee for three and a half hours in the Rayburn House Office Building on Capitol Hill September 21, 2016 in Washington, DC. Despite the lack of evidence against him, Koskinen is facing impeachment threats from conservatives in the House of Representatives for his role in the destruction of computer backups containing thousands of emails sought by Congress in its investigation of political targeting. (Photo by Chip Somodevilla/Getty Images)

WASHINGTON, DC - SEPTEMBER 21: Internal Revenue Service Commissioner John Koskinen talks to reporters after testifying before the House Judiciary Committee for three and a half hours in the Rayburn House Office Building on Capitol Hill September 21, 2016 in Washington, DC. Despite the lack of evidence against him, Koskinen is facing impeachment threats from conservatives in the House of Representatives for his role in the destruction of computer backups containing thousands of emails sought by Congress in its investigation of political targeting. (Photo by Chip Somodevilla/Getty Images)

WASHINGTON, DC - SEPTEMBER 21: Internal Revenue Service Commissioner John Koskinen leaves after testifying before the House Judiciary Committee for three and a half hours in the Rayburn House Office Building on Capitol Hill September 21, 2016 in Washington, DC. Despite the lack of evidence against him, Koskinen is facing impeachment threats from conservatives in the House of Representatives for his role in the destruction of computer backups containing thousands of emails sought by Congress in its investigation of political targeting. (Photo by Chip Somodevilla/Getty Images)