US politics

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

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

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 

Democratic U.S. presidential candidate Hillary Clinton arrives with Nevada State Assemblyman Nelson Araujo to purchase ice cream between campaign events in North Las Vegas

David Becker/Reuters

Democratic U.S. presidential candidate Hillary Clinton (L) arrives with Nevada State Assemblyman Nelson Araujo to purchase ice cream between campaign events in North Las Vegas, Nevada.

Jim Watson/AFP

Pope Francis arrives to address a joint meeting of Congress in Washington, DC. Pope Francis on Thursday urged the US Congress to help those fleeing war and poverty, and work to combat climate change, in a historic address to lawmakers

U.S. President Barack Obama talks to Pope Francis onstage as the "Old Guard" fife and drum corps marches past during an official welcome ceremony on the South Lawn at the White House in Washington...U.S. President Barack Obama (L) and Pope Francis watch onstage as the "Old Guard" fife and drum corps marches past during an official welcome ceremony on the South Lawn at the White House in Washington September 23, 2015

Jonathan Ernst /Reuters

U.S. President Barack Obama and Pope Francis watch onstage as the “Old Guard” fife and drum corps marches past during an official welcome ceremony on the South Lawn at the White House in Washington

US President Barack Obama and Japanese Prime Minister Shinzo Abe attend official welcoming ceremonies on the South Lawn of the White House in Washington, DC, April 28, 2015.

Mandel Ngan/AFP

US President Barack Obama and Japanese Prime Minister Shinzo Abe attend official welcoming ceremonies on the South Lawn of the White House in Washington, DC on Tuesday

A worker lowers himself from a scaffold in front of a Hillary Clinton sign near her campaign headquarters in the Brooklyn borough of New York, April 14, 2015. An unknown entity placed  Don t say  signs outside Clinton's Brooklyn Heights headquarters before her announcement Sunday

Brendan McDermid/Reuters

A worker lowers himself from a scaffold in front of a Hillary Clinton sign near her campaign headquarters in the Brooklyn borough of New York on Tuesday

Police remove a protester holding a sign as U.S. Secretary of State John Kerry testifies at a Senate Foreign Relations Committee hearing on Capitol Hill in Washington...Police remove a protester holding a sign as U.S. Secretary of State John Kerry testifies at a Senate Foreign Relations Committee hearing on "The President's Request for Authorization to Use Force Against ISIS: Military and Diplomatic Efforts" on Capitol Hill in Washington March 11, 2015.

Kevin Lamarque/Reuters

Police remove a protester holding a sign as US Secretary of State John Kerry testifies at a Senate Foreign Relations Committee hearing on “The President’s Request for Authorisation to Use Force Against Isis: Military and Diplomatic Efforts” on Capitol Hill in Washington on Wednesday

Anti-Zionist ultra-orthodox Jews of the Naturei Karta movement hold signs outside the Washington Convention Center where Israeli Prime Minister Benjamin Netanyahu addressed the American Israel Public Affairs Committee (AIPAC) policy conference inb Washington, DC, on March 2, 2015. Netanyahu is ramping up his mission to foil an emerging White House-backed nuclear deal with Iran with the speech to the powerful pro-Israel AIPAC lobby.

Nicholas Kamm/AFP

Anti-Zionist ultra-orthodox Jews of the Naturei Karta movement hold signs outside the Washington Convention Centre where Israeli Prime Minister Benjamin Netanyahu addressed the American Israel Public Affairs Committee (AIPAC) policy conference in Washington, DC, on Monday

Protesters listen during a hearing of the Senate Armed Services Committee on Capitol Hill on February 5, 2015 in Washington, DC. Witnesses testified about the use of the Guantanamo Detention Facility in Cuba and US detention policy.

Brendan Smialowski/AFP

Protesters listen during a hearing of the Senate Armed Services Committee on Capitol Hill on Thursday in Washington, DC. Witnesses testified about the use of the Guantanamo Detention Facility in Cuba and US detention policy

Scaffolding surrounds the U.S. Capitol Building while it undergoes repairs in Washington, D.C., U.S., on Wednesday, Nov. 5, 2014. Republicans roared back in the midterm elections on Tuesday, capturing control of the Senate from Democrats, winning crucial governor races and solidifying their majority in the U.S. House.

Andrew Harrer/Bloomberg

Scaffolding surrounds the U.S. Capitol Building while it undergoes repairs in Washington, D.C., U.S., on Wednesday. Republicans roared back in the midterm elections on Tuesday night, capturing control of the Senate from the Democrats

Election...The media sets up on the risers before Democrat Tom Wolf's rally in the Utz Arena of the York Expo Center in York, Pa. on Tuesday, Nov. 4, 2014. (AP Photo/York Daily Record, Jason Plotkin)

Jason Plotkin/AP

The media sets up on the risers before Democrat Tom Wolf’s rally in the Utz Arena of the York Expo Center in York Pennsylvania.