NEW YORK, NY - MAY 05: U.S. President Barack Obama greets 9-11 first reponders at a wreath laying ceremony at Ground Zero after accused 9-11 mastermind Osama bin Laden was killed on May 5, 2011 in New York City. (Photo by Mario Tama/Getty Images)
President Barack Obama in New York
NEW YORK, NY - MAY 05: U.S. President Barack Obama (C) smiles with police officers at a wreath laying ceremony at Ground Zero, after Osama bin Laden was killed on May 5, 2011 in New York City. (Photo by Mario Tama/Getty Images)
President Barack Obama in New York
NEW YORK, NY - MAY 05: U.S. President Barack Obama (R) and NYPD officer Stephanie Moses bow their heads at a wreath laying ceremony at Ground Zero after accused 9-11 mastermind Osama bin Laden was killed on May 5, 2011 in New York City. (Photo by Mario Tama/Getty Images)
President Barack Obama arrives at JFK
US President Barack Obama arrives at JFK international airport to board Air Force One to return to Washington, DC, after laying a wreath at the 9/11 Memorial in New York on May 5, 2011. (Photo credit should read JEWEL SAMAD/AFP/Getty Images)
President Barack Obama in New York
NEW YORK, NY - MAY 05: (L to R) New Jersey Governor Chris Christie, New York Governor Andrew Cuomo, U.S. President Barack Obama and New York City Mayor Michael Bloomberg attend a wreath laying ceremony at Ground Zero, after Osama bin Laden was killed on May 5, 2011 in New York City. (Photo by Mario Tama/Getty Images)
Obama Attends Wreath-Laying Ceremony At Ground Zero After Death Of Bin Laden
NEW YORK, NY - MAY 05: U.S. Rep. Anothony Weiner (D-NY) takes a photo after a wreath laying ceremony at Ground Zero with U.S. President Barack Obama, after Osama bin Laden was killed on May 5, 2011 in New York City. (Photo by Mario Tama/Getty Images)
President Barack Obama In New York
President Barack Obama (center) greets uniformed police and fire department officers at the World Trade Center site on May 5, 2011 in New York City. (credit: Spencer Platt/Getty Images)
President Barack Obama In New York
U.S. Senator Charles Schumer (D-NY) (4th L), C, U.S. Senator Kirsten Gillibrand (D-NY) (2nd L) and others look on at a wreath laying ceremony at Ground Zero with U.S. President Barack Obama, after Osama bin Laden was killed on May 5, 2011 in New York City. (credit: Mario Tama/Getty Images)
President Barack Obama In New York
President Barack Obama hugs Diane Wall, whose husband Glen Wall perished in the twin towers on September 11, 2001, as other victims' family members look on at a wreath laying ceremony at Ground Zero Zero after Osama bin Laden was killed on May 5, 2011 in New York City. 14-year-old Payton Wall, who asked the president if he could help her meet Justin Bieber, is in purple on the right. (credit: Mario Tama/Getty Images)
President Barack Obama In New York
President Barack Obama stands with members of the New York City Police Department at the First Precinct on May 5, 2011 in New York City. (credit: John Angelillo-Pool/Getty Images)
President Barack Obama In New York
President Barack Obama greets members of the New York City Fire and Police Departments after laying a wreath during a ceremony at Ground Zero after Osama bin Laden was killed on May 5, 2011 in New York City. (credit: John Angelillo-Pool/Getty Images)
President Barack Obama In New York
President Barack Obama stands with members of the New York City Fire and Police Departments after laying a wreath during a ceremony at Ground Zero after Osama bin Laden was killed on May 5, 2011 in New York City. (credit: John Angelillo-Pool/Getty Images)
President Barack Obama In New York
President Barack Obama walks with members of the New York City Fire and Police Departments holding a wreath during a ceremony at Ground Zero after Osama bin Laden was killed on May 5, 2011 in New York City. (credit: John Angelillo-Pool/Getty Images)
President Barack Obama In New York
US President Barack Obama (R) speaks with New York City Police Sergeant Stephanie Moses (L) after laying a wreath at the 9/11 Memorial at Ground Zero in Lower Manhattan May 5, 2011 in New York. (credit: STAN HONDA/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama (R) speaks with family members of victims of the September 11, 2001 World Trade Center attack after laying a wreath at the 9/11 Memorial at Ground Zero in Lower Manhattan on May 5, 2011 in New York. (credit: STAN HONDA/AFP/Getty Images)
President Barack Obama In New York
U.S. President Barack Obama (C) carries a wreath with police and firefighters looking on at a wreath laying ceremony at Ground Zero after accused 9-11 mastermind Osama bin Laden was killed on May 5, 2011 . (credit: Mario Tama/Getty Images)
President Barack Obama In New York
US President Barack Obama greets police officers at the First Precinct police station in lower Manhattan in New York on May 5, 2011. (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama greets police officers at the First Precinct police station in lower Manhattan in New York on May 5, 2011. (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama poses with police officers at the First Precinct police station in lower Manhattan in New York on May 5, 2011. (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama speaks to police officers at the First Precinct police station in lower Manhattan in New York on May 5, 2011. (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama poses with police officers at the First Precinct police station in lower Manhattan in New York on May 5, 2011. (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama poses with police officers at the First Precinct police station in lower Manhattan in New York on May 5, 2011. (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama bows his head after laying a wreath at the 9/11 Memorial in New York on May 5, 2011. (credit JEWEL SAMAD/AFP/Getty Images
US President Barack Obama (2nd-L) bows h
US President Barack Obama lays a wreath
US President Barack Obama greets police
US President Barack Obama arrives with s
Obama Attends Wreath-Laying Ceremony At Ground Zero After Death Of Bin Laden
Police and onlookers near Ground Zero aw
President Barack Obama In New York
US President Barack Obama greets firefighters at the Midtown Firehouse (Engine 54, Ladder 4, Battalion 9) on May 5, 2011 (credit JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
President Barack Obama visits members of the New York City Fire Department at the Engine 54 fire house on May 5, 2011 in New York City. (credit: John Angelillo-Pool/Getty Images)
President Barack Obama In New York
US President Barack Obama addresses firefighters at the Midtown Firehouse (Engine 54, Ladder 4, Battalion 9) on May 5, 2011. (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama addresses firefighters at the Midtown Firehouse (Engine 54, Ladder 4, Battalion 9) on May 5, 2011. (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama's bullet-proof limousine is parked in front of Engine 54 Firehouse on May 5, 2011 (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama greets firefighters at the Midtown Firehouse (Engine 54, Ladder 4, Battalion 9) on May 5, 2011 (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama visits Engine 54 Firehouse on May 5, 2011 (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama (C) looks at a display of name plates of firefighters who were killed in the 9/11 attacks as he visits the Midtown Firehouse (Engine 54, Ladder 4, Battalion 9) on May 5, 2011. (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama greets firefighters at the Midtown Firehouse (Engine 54, Ladder 4, Battalion 9) on May 5, 2011 (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama visits of Midtownâ Firehouse (Engine 54, Ladder 4, Battalion 9) on May 5, 2011 (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama disembarks Air Force One in New York on May 5, 2011. (credit: JEWEL SAMAD/AFP/Getty Images)
President Barack Obama In New York
US President Barack Obama shakes hand with people at JFK international airport in New York on May 5, 2011. (credit: JEWEL SAMAD/AFP/Getty Images)