Now Playing: Trump offers thoughts and prayers to those in the path of Hurricane Michael
Now Playing: Biden: Many Democratic 2020 contenders know foreign policy better than Trump
Now Playing: FiveThirtyEight Senate forecast update for Oct. 10, 2018
Now Playing: Trump on missing journalist: ‘We’ll get to the bottom of it’
Now Playing: FBI director defends Kavanaugh background investigation
Now Playing: DHS chief: U.S. faces ‘pandemic’ of cyber threats
Now Playing: Melania Trump weighs in on the #MeToo movement
Now Playing: Ivanka would be ‘dynamite’ as UN ambassador: Trump
Now Playing: Trump faces surprise resignation of UN ambassador
Now Playing: Trump jokes about his own impeachment
Now Playing: Trump claims Democrats trying to undermine Kavanaugh
Now Playing: The Big Vote: Issues, races and people that matter in the midterms
Now Playing: The Big Vote: March for Our Lives organizers encourage young people to vote
Now Playing: Trump announces plan to expand ethanol use at Iowa campaign rally
Now Playing: UN ambassador Nikki Haley resigns unexpectedly
Now Playing: Haley resigns as US ambassador to UN while Kavanaugh starts on the bench
Now Playing: Kanye West to meet with Trump at the White House
Now Playing: Did Brett Kavanaugh ceremony turn into a political rally?
Now Playing: Nikki Haley resigning as U.N. ambassador
Now Playing: Trump officials who have left the White House
