US President Barack Obama speaks during a press conference in the Brady Briefing Room of the White House on April 23, 2015 in Washington, DC. The White House admitted Thursday that a January US operation against an Al Qaeda compound near the Afghan-Pakistan border killed one American and one Italian hostage, along with an American member of the jihadist group. The White House identified the hostages killed in the operation against the border compound as US contractor Warren Weinstein and Italian aid worker Giovanni Lo Porto. AFP PHOTO/MANDEL NGAN (Photo credit should read MANDEL NGAN/AFP/Getty Images)
FREDERICK, MD - APRIL 21: Republican presidential candidate Sen. Ted Cruz (R-TX) campaigns at the Weinberg Theater April 21, 2016 in Frederick, Maryland. Maryland and four other northeastern states hold their primaries next Tuesday. (Photo by Win McNamee/Getty Images)
NEW YORK, NEW YORK - APRIL 13: Arab American Association of New York executive director Linda Sarsour speaks onstage at a campaign event for Democratic presidential candidate U.S. Senator Bernie Sanders (not pictured) at Washington Square Park on April 13, 2016 in New York City. (Photo by D Dipasupil/WireImage)
US Democratic presidential candidates Hillary Clinton (L) and Bernie Sanders arrive on stage for the CNN Democratic Presidential Debate at the Brooklyn Navy Yard on April 14, 2016, in New York.
Hillary Clinton and Bernie Sanders take their increasingly acrimonious battle for the Democratic White House nomination to a debate stage in Brooklyn on Thursday ahead of the key New York primary. / AFP / Jewel SAMAD (Photo credit should read JEWEL SAMAD/AFP/Getty Images)
PALM BEACH, FL - MARCH 11: Corey Lewandowski campaign manager for Republican presidential candidate Donald Trump speaks with the media before former presidential candidate Ben Carson gives his endorsement to Mr. Trump at the Mar-A-Lago Club on March 11, 2016 in Palm Beach, Florida. Presidential candidates continue to campaign before Florida's March 15th primary day. (Photo by Joe Raedle/Getty Images)
WASHINGTON, DC - DECEMBER 7: U.S. Sen. Bernie Sanders (I-VT) speaks to reporters on Capitol Hill on December 7, 2010 in Washington, DC. The Obama administration is pushing for Congress to extend Bush-era tax cuts in a compromise with Republicans. (Photo by Brendan Smialowski/Getty Images)
Hillary Clinton, former Secretary of State and 2016 Democratic presidential hopeful speaks during the 2015 integration immigration conference in Brooklyn, New York on December 14, 2015. AFP PHOTO/KENA BETANCUR / AFP / KENA BETANCUR (Photo credit should read KENA BETANCUR/AFP/Getty Images)
DALLAS, TX - SEPTEMBER 14: Republican presidential candidate Donald Trump speaks during a campaign rally at the American Airlines Center on September 14, 2015 in Dallas, Texas. More than 20,000 tickets have been distributed for the event. (Photo by Tom Pennington/Getty Images)
LAS VEGAS - NOVEMBER 11: Traffic passes by the famous sign welcoming motorists on the south end of the Las Vegas Strip November 11, 2005 in Las Vegas, Nevada. The Mandalay Bay Resort & Casino is in the background. (Photo by Ethan Miller/Getty Images)
Speaker of the House Paul Ryan (R-WI) addresses the 2016 American Israel Public Affairs Committee policy conference at the Verizon Center March 21, 2016 in Washington, DC. / AFP / Brendan Smialowski (Photo credit should read BRENDAN SMIALOWSKI/AFP/Getty Images)
LAREDO, TEXAS - JULY 23: Citizens watch as Republican Presidential candidate and business mogul Donald Trump leaves in his plane after his trip to the border on July 23, 2015 in Laredo, Texas. Trump's recent comments, calling some immigrants from Mexico as drug traffickers and rapists, have stirred up reactions on both sides of the aisle. Although fellow Republican presidential candidate Rick Perry has denounced Trump's comments and his campaign in general, U.S. Senator from Texas Ted-Cruz has so far refused to bash his fellow Republican nominee. (Photo by Matthew Busch/Getty Images)
TOPSHOT - Members of a brigade loyal to the Fajr Libya (Libya Dawn), an alliance of Islamist-backed fighters, drive pick up trucks mounted with machine guns during a military parade following battles against the Islamic State (IS) group, in the city of Sabratha, west of the capital Tripoli, on February 28, 2016.
On February 19, a US air strike near Sabratha targeted a suspected IS training camp, killing 50 people. / AFP / MAHMUD TURKIA (Photo credit should read MAHMUD TURKIA/AFP/Getty Images)
HICKORY, NC - MARCH 14: Republican presidential candidate Donald Trump addresses the crowd during a campaign rally at Lenoir-Rhyne University March 14, 2016 in Hickory, North Carolina. The North Carolina Republican primary will be held March 15. (Photo by Sean Rayford/Getty Images)
