US

Hillary Clinton...Democratic presidential candidate Hillary Clinton gestures during a commercial break at a CNN town hall style televised event at the University of South Carolina School of Law, in Columbia, S.C., Tuesday, Feb. 23, 2016. (AP Photo/Gerald Herbert)

  © Gerald Herbert/AP

Democrat presidential candidate Hillary Clinton gestures during a commercial break at a CNN town hall televised event at the University of South Carolina School of Law, in Columbia, US

Protesters carry placards outside an Apple store

Steven Senne/AP

Protesters carry placards outside an Apple store in Boston to protest the FBI obtaining a court order that requires Apple to make it easier to unlock an encrypted iPhone used by a gunman in December’s shooting in San Bernardino

Julio Cortez / AP Photo

A full moon rises over the Statue of Liberty, seen from the Port Liberte neighborhood of Jersey City, N.J

Mike Nelson / EPA

Supporters of US Republican presidential candidate businessman Donald Trump at a rally in Las Vegas, Nevada

Mario Anzuoni/Reuters

  

Demonstrators protesting for an increase in the minimum wage enter the media file center at the PBS NewsHour Democratic presidential candidate debate at the University of Wisconsin-Milwaukee

Win McNamee/Getty Images

Demonstrators protesting for an increase in the minimum wage enter the media file center at the PBS NewsHour Democratic presidential candidate debate at the University of Wisconsin-Milwaukee

President Barack Obama returns a salute as he boards Air Force One before his departure from Andrews Air Force Base, Maryland. USA

Pablo Martinez Monsivais/AP

President Barack Obama returns a salute as he boards Air Force One before his departure from Andrews Air Force Base

Win McNamee/Getty

Democratic presidential candidate, Sen. Bernie Sanders addresses supporters after winning the New Hampshire Democratic primary in Concord, New Hampshire. Sanders defeated Democratic presidential candidate Hillary Clinton in the first-in-the-nation primary

New Hampshire Residents Vote In The First-In-The-Nation New Hampshire Primary...A resident, right, hands an election official a Republican ballot at the town hall polling site during the New Hampshire presidential primary election in Harts Location, New Hampshire, U.S., on Tuesday, Feb. 9, 2016. According to the New Hampshire Secretary of State's office, the state has 383,834 voters who haven't declared a party affiliation, compared to 260,896 registered Republicans and 229,202 Democrats. Photographer: Andrew Harrer/Bloomberg

Andrew Harrer/Bloomberg

A resident, right, hands an election official a Republican ballot at the town hall polling site during the New Hampshire presidential primary election in Harts Location, New Hampshire, U.S., on Tuesday. According to the New Hampshire Secretary of State’s office, the state has 383,834 voters who haven’t declared a party affiliation, compared to 260,896 registered Republicans and 229,202 Democrats.

Presidential Candidate Marco Rubio Holds Retail Campaign Stops...An image of Senator Marco Rubio, a Republican from Florida and 2016 presidential candidate, is seen on his campaign bus as it sits outside the building which houses his campaign headquarters in Manchester, New Hampshire, U.S., on Monday, Feb. 8, 2016. Rubio, who surged to second place in polls after coming in third in the Iowa caucuses, spent Sunday trying to extinguish a political brushfire after he delivered the same canned answer three times within a matter of minutes at Saturday's presidential debate. Photographer: Daniel Acker/Bloomberg

Daniel Acker/Bloomberg

An image of Senator Marco Rubio, a Republican from Florida and 2016 presidential candidate, is seen on his campaign bus as it sits outside the building which houses his campaign headquarters in Manchester, New Hampshire, U.S 

Marco Rubio Campaigns Ahead Of New Hampshire Primary...NASHUA, NH - FEBRUARY 08:  Republican presidential candidate Sen. Marco Rubio (R-FL) sips coffee before doing a television interview at Norton's Classic Cafe during a campaign stop February 8, 2016 in Nashua, New Hampshire. Rubio is hoping for a good showing on Tuesday when people in New Hampsire head to the polls in the 'First in the Nation' presidential primary.  (Photo by Chip Somodevilla/Getty Images) **BESTPIX**

Chip Somodevilla/Getty

Republican presidential candidate Sen. Marco Rubio sips coffee before doing a television interview at Norton’s Classic Cafe during a campaign stop in Nashua, New Hampshire

Protected by a mosquito net, Nadia Gonzalez recovers from a bout of dengue fever at a hospital in Luque, Paraguay Friday, Feb. 5, 2016. Dengue, like the Zika virus, is transmitted by the same vector, the Aedes aegypti mosquito. Zika was discovered in a Ugandan forest in 1947 and until last year, the virus had never caused serious disease. It has now spread to more than 20 countries. (AP Photo/Jorge Saenz)

Jorge Saenz/AP

Protected by a mosquito net, Nadia Gonzalez recovers from a bout of dengue fever at a hospital in Luque, Paraguay. Dengue, like the Zika virus, is transmitted by the same vector, the Aedes aegypti mosquito

Democratic Presidential Candidates Hillary Clinton And Bernie Sanders Debate In Durham, New Hampshire...DURHAM, NH - FEBRUARY 04:  Democratic presidential candidates former Secretary of State Hillary Clinton walks on stage during a break as she debates with U.S. Sen. Bernie Sanders (I-VT) during their MSNBC Democratic Candidates Debate at the University of New Hampshire on February 4, 2016 in Durham, New Hampshire. This is the final debate for the Democratic candidates before the New Hampshire primaries.  (Photo by Justin Sullivan/Getty Images)

Justin Sullivan/Getty

Democratic presidential candidate Hillary Clinton walks on stage during a break as she debates with U.S. Sen. Bernie Sanders (I-VT) during their MSNBC Democratic Candidates Debate at the University of New Hampshire in Durham, New Hampshire. This is the final debate for the Democratic candidates before the New Hampshire primaries

Martin Shkreli, former CEO of Turing Pharmaceuticals LLC, arrives before a House Oversight and Government Reform hearing on "Developments in the Prescription Drug Market Oversight" on Capitol Hill in Washington...Martin Shkreli, (C) former CEO of Turing Pharmaceuticals LLC, arrives before a House Oversight and Government Reform hearing on "Developments in the Prescription Drug Market Oversight" on Capitol Hill in Washington February 4, 2016. REUTERS/Joshua Roberts      TPX IMAGES OF THE DAY

Joshua Roberts/Reuters

Martin Shkreli, former CEO of Turing Pharmaceuticals LLC, arrives before a House Oversight and Government Reform hearing on “Developments in the Prescription Drug Market Oversight” at Capitol Hill in Washington

A child sits on the ground and listens to U.S. Democratic presidential candidate Hillary Clinton speak to supporters during a campaign rally in Manchester, New Hampshire...A child sits on the ground and listens to U.S. Democratic presidential candidate Hillary Clinton speak to supporters during a campaign rally in Manchester, New Hampshire, February 3, 2016. REUTERS/Carlo Allegri

Carlo Allegri/Reuters

A child sits on the ground and listens to U.S. Democratic presidential candidate Hillary Clinton speak to supporters during a campaign rally in Manchester, New Hampshire

Miss Piggy, John Tuttle...Miss Piggy, with New York Stock Exchange Chief of Staff John Tuttle, rings the NYSE opening bell to highlight the season premier of Disney's "The Muppets" television show, Monday, Feb. 1, 2016. (AP Photo/Richard Drew)

Richard Drew/AP

Miss Piggy, with New York Stock Exchange Chief of Staff John Tuttle, rings the NYSE opening bell to highlight the season premier of Disney’s “The Muppets” television show

Presidential Candidate Hillary Clinton Holds Iowa Get Out The Caucus Rallies...A supporter waves signs supporting Hillary Clinton, former Secretary of State and 2016 Democratic presidential candidate, outside a campaign event at Abraham Lincoln High School in Des Moines, Iowa, U.S., on Sunday, Jan. 31, 2016. Hillary Clinton is holding onto a slim lead over Bernie Sanders in Iowa as Democrats prepare for Monday's caucuses, though an outpouring of young voters and those who say the system is rigged could enable Sanders to pull off an upset, according to a new poll. Photographer: Daniel Acker/Bloomberg

Daniel Acker/Bloomberg

A supporter waves signs supporting Hillary Clinton, former Secretary of State and 2016 Democratic presidential candidate, outside a campaign event at Abraham Lincoln High School in Des Moines, Iowa, U.S 

Brynn Anderson/AP

Supporters of Democratic presidential candidate Sen. Bernie Sanders cheer during a campaign stop, in Birmingham, Alabama 

A supporter of US Republican presidentia...A supporter of US Republican presidential candidate Donald Trump attends a rally at Liberty University in Lynchburg, Virginia, January 18, 2016.  / AFP / NICHOLAS KAMMNICHOLAS KAMM/AFP/Getty Images

Nicholas Kamm/AFP

A supporter of US Republican presidential candidate Donald Trump attends a rally at Liberty University in Lynchburg, Virginia 

A U.S. Air Force F15 fighter jet takes off from Kadena Air Base in Okinawa, southwestern Japan

Koji Ueda/AP

A U.S. Air Force F15 fighter jet takes off from Kadena Air Base in Okinawa, southwestern Japan