US President Barack Obama delivers remarks at the 39th annual Congressional Hispanic Caucus Institute Public Policy Conference and Annual Awards Gala in Washington, DC, on September 15, 2016. / AFP PHOTO / NICHOLAS KAMMNICHOLAS KAMM/AFP/Getty Images

U.S. President Barack Obama walks back to the Oval Office upon his return to the White House in Washington, D.C., U.S., September 15, 2016. REUTERS/Kevin Lamarque

GREENSBORO, NC - SEPTEMBER 15: Protesters hold signs as democratic presidential nominee former Secretary of State Hillary Clinton speaks during a campaign rally at UNC Greensboro on September 15, 2016 in Greensboro, North Carolina. Hillary Clinton is beginning to campaign again after taking three days off the trail to recover from pneumonia. Clinton will campaign in North Carolina and Washington D.C. (Photo by Justin Sullivan/Getty Images)

GREENSBORO, NC - SEPTEMBER 15: Democratic presidential nominee former Secretary of State Hillary Clinton speaks during a campaign rally at UNC Greensboro on September 15, 2016 in Greensboro, North Carolina. Hillary Clinton is beginning to campaign again after taking three days off the trail to recover from pneumonia. Clinton will campaign in North Carolina and Washington D.C. (Photo by Justin Sullivan/Getty Images)

GREENSBORO, NC - SEPTEMBER 15: Democratic presidential nominee former Secretary of State Hillary Clinton speaks during a campaign rally at UNC Greensboro on September 15, 2016 in Greensboro, North Carolina. Hillary Clinton is beginning to campaign again after taking three days off the trail to recover from pneumonia. Clinton will campaign in North Carolina and Washington D.C. (Photo by Justin Sullivan/Getty Images)

GREENSBORO, NC - SEPTEMBER 15: Democratic presidential nominee former Secretary of State Hillary Clinton speaks during a campaign rally at UNC Greensboro on September 15, 2016 in Greensboro, North Carolina. Hillary Clinton is beginning to campaign again after taking three days off the trail to recover from pneumonia. Clinton will campaign in North Carolina and Washington D.C. (Photo by Justin Sullivan/Getty Images)

GREENSBORO, NC - SEPTEMBER 15: Democratic presidential nominee former Secretary of State Hillary Clinton speaks during a campaign rally at UNC Greensboro on September 15, 2016 in Greensboro, North Carolina. Hillary Clinton is beginning to campaign again after taking three days off the trail to recover from pneumonia. Clinton will campaign in North Carolina and Washington D.C. (Photo by Justin Sullivan/Getty Images)

GREENSBORO, NC - SEPTEMBER 15: Democratic presidential nominee former Secretary of State Hillary Clinton greets supporters during a campaign rally at UNC Greensboro on September 15, 2016 in Greensboro, North Carolina. Hillary Clinton is beginning to campaign again after taking three days off the trail to recover from pneumonia. Clinton will campaign in North Carolina and Washington D.C. (Photo by Justin Sullivan/Getty Images)