CLEVELAND, OH - JULY 21: Republican presidential candidate Donald Trump gives two thumbs up to the crowd during the evening session on the fourth day of the Republican National Convention on July 21, 2016 at the Quicken Loans Arena in Cleveland, Ohio. Republican presidential candidate Donald Trump received the number of votes needed to secure the party's nomination. An estimated 50,000 people are expected in Cleveland, including hundreds of protesters and members of the media. The four-day Republican National Convention kicked off on July 18. (Photo by Chip Somodevilla/Getty Images)
CLEVELAND, OH - JULY 19: Attendees watch the preperations before the start of the second day of the Republican National Convention on July 19, 2016 at the Quicken Loans Arena in Cleveland, Ohio. An estimated 50,000 people are expected in Cleveland, including hundreds of protesters and members of the media. The four-day Republican National Convention kicked off on July 18. (Photo by Jeff Swensen/Getty Images)
WESTFIELD, IN - JULY 12: Republican presidential candidate Donald Trump greets Indiana Gov. Mike Pence at the Grand Park Events Center on July 12, 2016 in Westfield, Indiana. Trump is campaigning amid speculation he may select Indiana Gov. Mike Pence as his running mate. (Photo by )
TOPSHOT - Leader of the United Kingdom Independence Party (UKIP), Nigel Farage (C) speaks during a press conference near the Houses of Parliament in central London on June 24, 2016.
Britain has voted to leave the European Union by 51.9 percent to 48.1 percent, final results from all 382 of Britain's local counting centres showed on Friday. / AFP / GLYN KIRK (Photo credit should read GLYN KIRK/AFP/Getty Images)
US Speaker of the House Paul Ryan addresses his weekly briefing after meeting Republican presidential candidate Donald Trump on Capitol Hill in Washington, DC, on May 12, 2016.
Ryan and Trump said they had taken a "very positive step" towards bridging party divisions sparked by the billionaire's White House bid. / AFP / Nicholas Kamm (Photo credit should read NICHOLAS KAMM/AFP/Getty Images)
DES MOINES, IA-DECEMBER 11: Republican Presidential Candidate Donald Trump speaks at a town hall style campaign rally at the Varied Industries Building at Iowa State Fair Grounds on December 11, 2015 in Des Moines, Iowa. Recent polls continue to show Trump holding a lead in the race for the Republican nomination for President. (Photo by Steve Pope/Getty Images
Republican presidential candidates participate in the Republican Presidential Candidates Debate February 6, 2016 at St. Anselm's College Institute of Politics in Manchester, New Hampshire. From left are: Jeb Bush, Marco Rubio, Donald Trump, and Ted Cruz.
Seven Republicans campaigning to be US president are in a fight for survival in their last debate Saturday before the New Hampshire primary, battling to win over a significant number of undecided voters. / AFP / JEWEL SAMAD (Photo credit should read )
US Secretary of State John Kerry (2nd L) meets with Montenegro's Foreign Minister Igor Luksic during the NATO ministerial meetings at the NATO headquarters in Brussels on December 2, 2015
NATO foreign ministers on Wednesday invited Montenegro to join the US-led military alliance, a move Russia has repeatedly warned against as a threat to stability in the western Balkans. / AFP / POOL / JONATHAN ERNST (Photo credit should read JONATHAN ERNST/AFP/Getty Images)
Real estate mogul Donald Trump announces his bid for the presidency in the 2016 presidential race during an event at the Trump Tower on the Fifth Avenue in New York City on June 16, 2015. Trump, one of America's most flamboyant and outspoken billionaires, threw his hat into the race Tuesday for the White House, promising to make America great again. The 69-year-old long-shot candidate ridiculed the country's current crop of politicians and vowed to take on the growing might of China in a speech launching his run for the presidency in 2016. "I am officially running for president of the United States and we are going to make our country great again," he said from a podium bedecked in US flags at Trump Tower on New York's Fifth Avenue. The tycoon strode onto the stage after sailing down an escalator to the strains of "Rockin' In The Free World" by Canadian singer Neil Young after being introduced by daughter Ivanka. His announcement follows years of speculation that the man known to millions as the bouffant-haired host of American reality TV game show "The Apprentice" would one day enter politics. Trump identifies himself as a Republican, and has supported Republican candidates in the past. But in his announcement speech he did not explicitly say if he was running for the party's nomination or as an independent.AFP PHOTO/ KENA BETANCUR (Photo credit should read KENA BETANCUR/AFP/Getty Images)