Now Playing: Trump reportedly demanded Mueller be fired

Now Playing: White House reveals new immigration proposal

Now Playing: Pa. congressman won't run for re-election despite denying sexually harassing aide

Now Playing: Trump demanded Mueller be fired, but backed off: Report

Now Playing: Trump proposes path to citizenship for 1.8M

Now Playing: White House to offer pathway to citizenship for 1.8 million in new immigration deal

Now Playing: Trump comes to Davos with an argument to make

Now Playing: Trump says he's willing to talk to Mueller under oath

Now Playing: Republicans claim FBI officials' texts show anti-Trump bias

Now Playing: The full 'secret society' text between FBI agents: Was it meant in jest?

Now Playing: GOP escalate attacks on Robert Mueller's investigation

Now Playing: Trump: I am willing to talk to Mueller under oath

Now Playing: Trump says he wants to sit down with Robert Mueller under oath

Now Playing: White House doesn't denyTrump questioned acting FBI director about 2016 vote

Now Playing: Alex Azar: Everything you need to know

Now Playing: Russia investigation heats up as questions surround Trump's meeting with McCabe

Now Playing: CNN anchor Don Lemon calls out Trump

Now Playing: First lady Melania Trump skips Davos trip

Now Playing: White House to release 'legislative framework' on immigration

Now Playing: Special counsel seeking interview with Trump: Sources