Democratic presidential nominee Hillary Clinton and vice presidential candidate Tim Kaine are surrounded by falling ballons at the end on the fourth day of the Democratic National Convention, July 28, 2016, in Philadelphia.

Democratic presidential candidate Hillary Clinton is embraced by her husband, former President Bill Clinton, after accepting the nomination on the fourth day of the Democratic National Convention, July 28, 2016, in Philadelphia.

Democratic presidential candidate Hillary Clinton and running mate Tim Kaine wave to delegates and attendees at the end on the fourth day of the Democratic National Convention, July 28, 2016, in Philadelphia.

Democratic presidential candidate Hillary Clinton waves to the crowd as she arrives on stage during the fourth day of the Democratic National Convention, July 28, 2016, in Philadelphia.

Bernie Sanders listens as Democratic presidential nominee Hillary Clinton address the Democratic National Convention in Philadelphia, July 28, 2016.

Former President Bill Clinton becomes emotional as he listens to his daughter Chelsea Clinton introduce her mother, Democratic presidential candidate Hillary Clinton, on the fourth day of the Democratic National Convention, July 28, 2016, in Philadelphia.

Democratic presidential nominee Hillary Clinton arrives on stage after her daughter Chelsea Clinton introduced her on the fourth day of the Democratic National Convention, July 28, 2016, in Philadelphia.

Singer Katy Perry performs during the fourth day of the Democratic National Convention at the Wells Fargo Center, July 28, 2016 in Philadelphia.

Kareem Abdul-Jabbar takes the stage at the Democratic National Convention in Philadelphia, July 28, 2016.

Retired USMC General John Allen, former Commander, International Security Assistance Forces, and Commander, United States Forces in Afghanistan, speaks at the Democratic National Convention in Philadelphia, July 28, 2016.

Delegates hold signs and show support for Bernie Sanders by wearing glow-in-the-dark yellow tshirts during the final day of the Democratic National Convention on July 28, 2016, in Philadelphia.

Khizr Khan holds his personal copy of the Constitution while addressing delegates at the Democratic National Convention on July 28, 2016, in Philadelphia. Khizr Khan's son, Humayun S. M. Khan, was a University of Virginia graduate and enlisted in the U.S. Army. Khan was one of 14 American Muslims who died serving the United States in the ten years after the September 11, 2001 terrorist attacks.

Delegates stand and cheer as Reverend William Barber delivers a speech on the fourth day of the Democratic National Convention, July 28, 2016 in Philadelphia.

A delegate recites the Pledge of Allegiance during the final day of the Democratic National Convention on July 28, 2016, in Philadelphia.

Sheila E performs during the final day of the Democratic National Convention in Philadelphia, July 28, 2016.

Louisiana delegates appear on the floor of the Wells Fargo Center in Philadelphia, on the third day of the Democratic National Convention, July 27, 2016.

The Democratic women of the U.S. Senate take the stage on the final day of the Democratic National Convention in Philadelphia, July 28, 2016.

Rep. Tammy Duckworth on the fourth day of the Democratic National Convention at the Wells Fargo Center, July 28, 2016 in Philadelphia.

Wisconsin delegates cheer during the fourth and final day of the Democratic National Convention, July 28, 2016 in Philadelphia.

LGBT rights activist Sarah McBride and co-Chair of the Congressional LGBT Equality Caucus, Congressman Sean Patrick Maloney, acknowledge applause at the end of their address on the fourth and final day of the Democratic National Convention on July 28, 2016, in Philadelphia.

Delegates partake in the invocation on the fourth day of the Democratic National Convention at the Wells Fargo Center, July 28, 2016, in Philadelphia.

Singer Carole King rehearses before the start of the final day of the Democratic National Convention in Philadelphia, July 28, 2016.

President Barack Obama and Democratic presidential candidate Hillary Clinton wave to the crowd following President Obama's remarks on the third day of the Democratic National Convention, July 27, 2016 in Philadelphia.

President Barack Obama is joined by Democratic presidential nominee Hillary Clinton after his address to the Democratic National Convention at the Wells Fargo Center in Philadelphia, July 27, 2016.

Delegates cheer as President Barack Obama addresses the delegates on the third day of the Democratic National Convention in Philadelphia, July 27, 2016.

President Barack Obama speaks during the third day of the Democratic National Convention, July 27, 2016, in Philadelphia.

Vice President candidate Tim Kaine greets Rev. Jesse Jackson after delivering remarks on the third day of the Democratic National Convention, July 27, 2016 in Philadelphia.

Vice presidential candidate Tim Kaine kisses his wife Anne Holton after delivering remarks on the third day of the Democratic National Convention, July 27, 2016 in Philadelphia.

Democratic vice presidential candidate, Sen. Tim Kaine, takes the stage on the third day of the Democratic National Convention in Philadelphia, July 27, 2016.

Vice presidential candidate Sen. Tim Kaine accepts the nomination at the Democratic National Convention in Philadelphia, July 27, 2016.

Lenny Kravitz performs during the third day of the Democratic National Convention, July 27, 2016, in Philadelphia.

Former New York City Mayor Michael Bloomberg gestures to attendees after delivering remarks on the third day of the Democratic National Convention, July 27, 2016, in Philadelphia.

Former President Bill Clinton cheers as former New York City mayor Michael Bloomberg addresses the crowd on the third evening of the Democratic National Convention in Philadelphia, July 27, 2016.

Vice President Joe Biden waves to the crowd as he arrives to deliver remarks on the third day of the Democratic National Convention, July 27, 2016, in Philadelphia.

Attendees chant during former Secretary of Defense Leon Panetta's speech on the third day of the Democratic National Convention, July 27, 2016, in Philadelphia.

Delegates hold hands while singing "What the World Needs Now Is Love" along with performers on the third day of the Democratic National Convention, July 27, 2016, in Philadelphia.

Entertainers sing "What the World Needs Now" during the third day of the Democratic National Convention in Philadelphia, July 27, 2016.

Former Congresswoman Gabby Giffords walks on stage with her husband, retired NASA Astronaut and Navy Captain Mark Kelly, after delivering remarks on the third day of the Democratic National Convention at the Wells Fargo Center, July 27, 2016 in Philadelphia.

The South Carolina delegation hold alternate versions of the symbol of their state flag as tribute to victims of the Mother Emanuel Church shooting, at the Democratic National Convention in Philadelphia, July 27, 2016.

Christine Leinonen, mother of Pulse nightclub victim Christopher 'Dru' Leinonen, delivers remarks along with survivors Jose Arriagada and Brandon Wolf, during the third day of the Democratic National Convention, July 27, 2016 in Philadelphia.

Sen. Wesley Bishop of New Orleans, a Hillary Clinton supporter, speaks with Colorado delegate Chris Davis, a supporter of Bernie Sanders, on the floor during the third day of the Democratic National Convention, July 27, 2016, in Philadelphia.

Sen. Minority Leader Harry Reid walks on stage with his wife Landra Gould on the third day of the Democratic National Convention, July 27, 2016, in Philadelphia.

A delegate wears stickers in support of Democratic presidential candidate Hillary Clinton on the third day of the Democratic National Convention, July 27, 2016 in Philadelphia.

Members of the Congressional Black Caucus, including, from left, Reps. Charles Rangel, John Conyers and John Lewis, acknowledge the audience as they take the stage at the Democratic National Convention in Philadelphia, July 27, 2016.

Former Massachusetts Gov. Michael Dukakis takes picture with delegates during the third day of the Democratic National Convention in Philadelphia, July 27, 2016.

Virginia delegates cheer as Sen. Tim Kaine, officially become the vice presidential nominee during the third day session of the Democratic National Convention in Philadelphia, July 27, 2016.

Delegates raise an American flag during the opening of the third day of the Democratic National Convention at the Wells Fargo Center, July 27, 2016 in Philadelphia.

Recording artist Alicia Keys performs "In Common" at the Democratic National Convention in Philadelphia, July 26, 2016.

Delegates watch Hillary Clinton speak live from New York during the Democratic National Convention, July 26, 2016 in Philadelphia.

Actress Meryl Streep addresses the Democratic National Convention at the Wells Fargo Center, July 26, 2016 in Philadelphia.

Delegates hold up signs and cheer on the second day of the Democratic National Convention at the Wells Fargo Center, July 26, 2016 in Philadelphia.

Former President Bill Clinton delivers remarks on the second day of the Democratic National Convention at the Wells Fargo Center, July 26, 2016 in Philadelphia.

Sen. Elizabeth Warren, left, and her husband Bruce Mann applaud with Chelsea Clinton and her husband Marc Mezvinsky during the Democratic National Convention in Philadelphia, July 26, 2016.

Former President Bill Clinton acknowledges the crowd as he takes the stage at the Democratic National Convention in Philadelphia. July 26, 2016.

Former Secretary of State Madeleine Albright takes the stage during the second day session of the Democratic National Convention in Philadelphia, July 26, 2016.

Former Governor of Vermont Howard Dean speaks during the second day of the Democratic National Convention, July 26, 2016 in Philadelphia.

Members of the Eagle Academy listen to speakers during the Democratic National Convention at the Wells Fargo Center in Philadelphia, July 26, 2016.

Singer Andra Day performs during the second day of the Democratic National Convention in Philadelphia, July 26, 2016.

Sandra Bland's mother, Geneva Reed-Veal, second from right, speaks alongside other mothers that have lost children to gun violence, part of the Mothers of the Movement group, during the second day of the Democratic National Convention, July 26, 2016, in Philadelphia.

Women hold a U.S. flag as they listen to mothers that have lost children to gun violence, part of the Mothers of the Movement group, speak during the second day of the Democratic National Convention, July 26, 2016 in Philadelphia.

Actress Elizabeth Banks arrives on stage while the song, 'We Are the Champions' by Queen plays, during the second day of the Democratic National Convention at the Wells Fargo Center, July 26, 2016 in Philadelphia. 25.

House Minority Leader Nancy Pelosi stands on stage with Democratic women house members during the second day of the Democratic National Convention in Philadelphia, July 26, 2016.

Sen. Bernie Sanders stands with the Vermont delegation and calls to stop the roll call and nominate Hillary Clinton by acclamation on the second day of the Democratic National Convention, July 26, 2016, in Philadelphia.

Delegates celebrate after formally nominating Democratic presidential candidate Hillary Clinton on the second day of the Democratic National Convention, July 26, 2016 in Philadelphia.

Sen. Bernie Sanders reacts after his brother Larry Sanders, cast a vote for him during roll call for Democrats Abroad at the Democratic National Convention in Philadelphia, July 26, 2016. Sanders' wife, Jane O'Meara Sanders is at left.

Votes are recorded during roll call on the second day of the Democratic National Convention in Philadelphia, July 26, 2016.

Wisconsin delegates take their seats before the start of the second day session of the Democratic National Convention in Philadelphia, July 26, 2016.

Actress Meryl Streep tries out the podium prior to the start of the second day of the Democratic National Convention at the Wells Fargo Center, July 26, 2016 in Philadelphia.

Sen. Bernie Sanders walks off stage after delivering remarks on the first day of the Democratic National Convention, July 25, 2016, in Philadelphia.

Sen. Bernie Sanders speaks during the first day of the Democratic National Convention in Philadelphia, July 25, 2016.

A disappointed supporter for Sen. Bernie Sanders, holds up a sign during the first day of the Democratic National Convention in Philadelphia, July 25, 2016.

Delegates stand and cheer as first lady Michelle Obama delivers remarks on the first day of the Democratic National Convention, July 25, 2016, in Philadelphia.

First lady Michelle Obama addresses the Democratic National Convention in Philadelphia, July 25, 2016.

Former President Bill Clinton listens as First Lady Michelle Obama speak at the Democratic National Convention in Philadelphia, July 25,2016.

Sen. Elizabeth Warren greets Joseph P. Kennedy, III during Day 1 of the Democratic National Convention in Philadelphia.

Sen. Cory Booker speaks at the Democratic National Convention in Philadelphia, July 25, 2016.

Sen. Cory Booker greets Eva Longoria after she introduced him at the Democratic National Convention in Philadelphia, July 25, 2016.

Recording artist Paul Simon performs at the Democratic National Convention in Philadelphia, July 25, 2016.

Sanjay Patel shows his support for Sen. Bernie Sanders by wearing a special jacket during the first day of the Democratic National Convention in Philadelphia, July 25, 2016.

US Senator Al Franken (L) and comedian Sarah Silverman share a moment during Day 1 of the Democratic National Convention in Philadelphia, Pennsylvania, July 25, 2016.

Former professional basketball player Jarron Collins introduces his twin brother Jason Collins during the first day of the Democratic National Convention in Philadelphia, July 25, 2016.

Karla Ortiz arrives on stage with her mother Francisca Ortiz at the Democratic National Convention in Philadelphia, Pennsylvania, July 25, 2016. Karla is an American citizen, but her mother is undocumented.

AFL-CIO President Richard Trumka speaks alongside Lee Saunders, President of American Federation of State, County and Municipal Employees, at the Democratic National Convention in Philadelphia, July 25, 2016.

Bernie Sanders supporters and delegates chant his name and yell in protest during the Convention Rules Committee report at the start of the first session at the Democratic National Convention in Philadelphia, July 25, 2016.

Rep. Elijah Cummings delivers a speech on the first day of the Democratic National Convention at the Wells Fargo Center, July 25, 2016, in Philadelphia.

Delegates hold up signs protesting the Trans-Pacific Partnership (TPP) on the first day of the Democratic National Convention at the Wells Fargo Center, July 25, 2016, in Philadelphia.

Baltimore's Mayor Stephanie Rawlings-Blake raises the gavel as she calls the convention to order during the first day of the Democratic National Convention in Philadelphia, July 25, 2016.

Florida delegate Lavon Bracy arrives on the convention floor before the start of the first day session of the Democratic National Convention in Philadelphia, July 25, 2016.

Singer songwriter Paul Simon runs through a sound check at the Wells Fargo Center before the start of the Democratic National Convention in Philadelphia, July 25, 2016.

Former Sen. Rick Santorum talks with reporter Carl Bernstein on the first day of the Democratic National Convention at the Wells Fargo Center, July 25, 2016, in Philadelphia.

Sen. Bernie Sanders walks out on stage prior to the start of the Democratic National Convention at the Wells Fargo Center, July 25, 2016, in Philadelphia.

Sen. Al Franken runs through a rehearsal before the start of the first day session of the Democratic National Convention in Philadelphia, July 25, 2016.