Hillary rallied supporters at the Pzazz! Resort Hotel in Burlington, Iowa.

- Democratic
presidential candidate Hillary Clinton greets supporters after holding a
campaign event in Burlington, Iowa, Wednesday, Jan. 20, 2016. (AP
Photo/Patrick Semansky)

- U.S.
Democratic presidential candidate Hillary Clinton arrives for an event
at a hotel in Burlington, Iowa, January 20, 2016. REUTERS/Aaron P.
Bernstein

- Democratic
presidential candidate Hillary Clinton speaks at the Pzazz! Resort
Hotel in Burlington, Iowa, January 20, 2016. REUTERS/Aaron P. Bernstein

- Democratic
presidential candidate Hillary Clinton speaks during a campaign event
in Burlington, Iowa, Wednesday, Jan. 20, 2016. (AP Photo/Patrick
Semansky)

- Democratic
presidential candidate Hillary Clinton waves to supporters after an
event at the Pzazz! Resort Hotel in Burlington, Iowa, January 20, 2016.
REUTERS/Aaron P. Bernstein

- Supporters
listen to Democratic presidential candidate Hillary Clinton speak at a
campaign event in Burlington, Iowa, Wednesday, Jan. 20, 2016. (AP
Photo/Patrick Semansky)

- Supporters
wait for a campaign event featuring Democratic presidential candidate
Hillary Clinton to begin in Burlington, Iowa, Wednesday, Jan. 20, 2016.
(AP Photo/Patrick Semansky)

- People
listen as Democratic presidential candidate Hillary Clinton during a
campaign event in Burlington, Iowa, Wednesday, Jan. 20, 2016. (AP
Photo/Patrick Semansky)

- Supporters
cheer as they listen to Democratic presidential candidate Hillary
Clinton speak at a campaign event in Burlington, Iowa, Wednesday, Jan.
20, 2016. (AP Photo/Patrick Semansky)

- Democratic
presidential candidate Hillary Clinton gestures as she speaks during a
campaign event in Burlington, Iowa, Wednesday, Jan. 20, 2016. (AP
Photo/Patrick Semansky)

- A
supporter of Democratic presidential candidate Hillary Clinton is seen
through a curtain as he walks backstage before a campaign event
featuring Clinton in Burlington, Iowa, Wednesday, Jan. 20, 2016. (AP
Photo/Patrick Semansky)

- U.S.
Democratic presidential candidate Hillary Clinton speaks at a hotel in
Burlington, Iowa, January 20, 2016. REUTERS/Aaron P. Bernstein

- Kayla
Kaminski, second from left, laughs as she waits for a campaign event
featuring Democratic presidential candidate Hillary Clinton to begin in
Burlington, Iowa, Wednesday, Jan. 20, 2016. (AP Photo/Patrick Semansky)