GOLDEN, CO - OCTOBER 29: Republican presidential nominee Donald Trump addresses a campaign rally in the Rodeo Arena at the Jefferson County Fairgrounds October 29, 2016 in Golden, Colorado. The Federal Bureau of Investigation announced Friday it discovered emails pertinent to the closed investigation of Democratic presidential nominee Hillary Clinton's private email server and are looking to see if they improperly contained classified information. Trump said "I think it's the biggest story since Watergate." (Photo by Chip Somodevilla/Getty Images)
Exxon Mobil chairman and CEO Rex Tillerson speaks at a discussion organized by the Economic Club of Washington on the energy innovations that have led to a new era of energy abundance for North America in Washington, DC on March 12, 2015. AFP PHOTO/NICHOLAS KAMM (Photo credit should read NICHOLAS KAMM/AFP/Getty Images)
WASHINGTON, DC - AUGUST 04: Senate Majority Leader Mitch McConnell (R-KY) (C), Sen. Roger Wicker (R-MS) (L) and Sen. John Cornyn (R-TX) prepare to speak to reporters after the weekly Senate Republican policy luncheon at the U.S. Capitol August 4, 2015 in Washington, DC. McConnell and his leadership team said they will work to pass a cybersecurity bill before the end of the week when the Senate will break for four weeks. (Photo by Chip Somodevilla/Getty Images)
DORAL, FL - JULY 27: Republican presidential candidate Donald Trump holds a press conference at Trump National Doral on July 27, 2016 in Doral, Florida. Trump spoke about the Democratic Convention and called on Russia to find Hillary Clinton's deleted e-mails. (Photo by Gustavo Caballero/Getty Images)
FAYETTEVILLE, NC - DECEMBER 06: President-elect Donald Trump shakes the hand of retired U.S. Marine General James Mattis after naming him Secretary of Defense at Crown Coliseum on December 6, 2016 in Fayetteville, North Carolina. Trump took time off from selecting the cabinet for his incoming administration to celebrate his victory in the general election. (Photo by Sara D. Davis/Getty Images)
Retired Lt. Gen. Michael Flynn arrives at the Trump Tower for meetings with US President-elect Donald Trump, in New York on November 17, 2016. / AFP / Eduardo Munoz Alvarez (Photo credit should read EDUARDO MUNOZ ALVAREZ/AFP/Getty Images)
RALEIGH, NC - JULY 5: Presumptive Republican presidential nominee Donald Trump stands next to Sen. Bob Corker (R-TN) during a campaign event at the Duke Energy Center for the Performing Arts on July 5, 2016 in Raleigh, North Carolina. Earlier in the day Hillary Clinton campaigned in Charlotte, North Carolina with President Barack Obama. (Photo by Sara D. Davis/Getty Images)
MESA, AZ - DECEMBER 16: Republican presidential candidate Donald Trump speaks to guest gathered during a campaign event at the International Air Response facility on December 16, 2015 in Mesa, Arizona. Trump is in Arizona the day after the Republican Presidential Debate hosted by CNN in Las Vegas, Nevada. (Photo by Ralph Freso/Getty Images)
TOPSHOT - US Democratic presidential candidate Hillary Clinton leaves the stage during a break as she participates in the MSNBC Democratic Candidates Debate with Bernie Sanders at the University of New Hampshire in Durham on February 4, 2016.
Clinton and Sanders face off on February 4, in the first debate since their bruising Iowa clash that the former secretary of state won by a hair, as they gear for a battle royale in New Hampshire. / AFP / Jewel Samad (Photo credit should read JEWEL SAMAD/AFP/Getty Images)
US President Barack Obama speaks during a campaign event in Denver, Colorado, on May 23, 2012. Obama may have made his name peddling hope and change, but his aspirational politics concealed a ruthless streak now being turned on the man who wants his job: Mitt Romney. President Obama and his hard-eyed political consultants have unleashed a long-planned attack on the Republican's corporate past, seeking to turn November's election on Romney's character rather than his own economic record. AFP PHOTO/Jewel Samad (Photo credit should read JEWEL SAMAD/AFP/GettyImages)
AVONDALE, AZ - MARCH 04: Four F-16's, 310th FS, "Top Hats" fly over during the national anthem before the NASCAR Sprint Cup Series SUBWAY Fresh Fit 500 at Phoenix International Raceway on March 4, 2012 in Avondale, Arizona. (Photo by Christian Petersen/Getty Images)