eating away at Vladimir Putin.

>> The FBI detected more

attempts...

>> Russian hackers are behind

those attacks.

>> NARRATOR: America in the

crosshairs.

>> This is the first time they

have gone out and weaponized

that information.

>> He's going to employ whatever

means he can to undermine the

United States.

>> NARRATOR: Tonight on

"Frontline," in a special

two-part investigation, the epic

inside story of "Putin's

Revenge."

>> We are now only a few days

away from electing the next

president of the United

States...

>> ...turning its attention

back to the election...

>> ...with the election just

days away...

>> NARRATOR: Election Day 2016.

As Americans headed to the

polls, U.S. intelligence

agencies were on high alert.

>> ...making the urgent push to

get out the vote.

>> Well, in the days before the

election, there was constant

interaction between the experts

at C.I.A., FBI, and NSA.

We were monitoring and using our

collection capabilities to

understand what the Russians

might have up their sleeve at

the 11th hour.

>> Breaking news here: Wikileaks

is about to release

"significant material tied to

Hillary Clinton."

>> The campaign is doing damage

control tonight after Wikileaks

released...

>> NARRATOR: The intelligence

agencies had been tracking a

multi-pronged effort to

influence voters: leaks of

hacked emails; ads on Facebook

and Google; on social media,

trolls and bots spreading fake

news-- all, they believed,

connected to Russian President

Vladimir Putin.

>> This was the most aggressive

and most direct and most

assertive campaign that the

Russians ever mounted in the

history of our elections.

And what characterized this

were the variety and intensity

of the techniques that they

employed.

>> NARRATOR: Now they detected

what they call O.P.E.--

operational preparation of the

environment.

>> The Russians will map the

architecture and the

environment of their targets.

>> NARRATOR: The target: state

electoral systems, registration

databases, voter information.

>> I'll never forget one day,

John Brennan said to me, "I'm

going to come brief you."

Now, it was not often that the

C.I.A. director, by himself,

came to DHS to meet with me, by

myself, to share intelligence.

>> NARRATOR: Brennan had told

Johnson the cyber-intrusions,

traced to Russia, could be the

first step in a plan to directly

interfere with voting.

>> The thing that immediately

has to come to you is, "Hey,

somebody might be trying to

eliminate from the rolls voters

in key states, in key precincts

through a very targeted, careful

effort."

You could really do a lot of

damage.

>> ...Going to the polls,

casting their ballots...

>> History will be made today...

>> NARRATOR: Inside the

administration, the question:

Just how far would Putin go?

>> I didn't know if the Russians

were going to do anything at

all.

And I thought if they did, it

clearly would be a sign that

Putin had authorized an

aggressive assault against this

country that to me would have

been tantamount to, to war.

♪ ♪

>> NARRATOR: It would be

Vladimir Putin's revenge for a

lifetime of grievances.

>> Mr. Gorbachev, tear down

this wall.

>> NARRATOR: Reviving the old

Cold War with new weapons.

>> We have the responsibility to

advance freedom and democracy.

>> NARRATOR: An epic struggle.

>> Everywhere that freedom

stirs, let tyrants fear.

>> NARRATOR: Between the leader

of Russia and American

democracy.

>> The United States will

continue to stand up for

democracy and the universal

rights that all human beings

deserve.

(man speaking Russian)

>> NARRATOR: The story begins on

New Year's Eve 1999.

In Moscow, the future of Russia

was about to change.

With his country in turmoil,

President Boris Yeltsin had an

announcement to make.

>> President Yeltsin rose on

immense popularity, his sense of

love and admiration, was

progressively losing that.

>> NARRATOR: Across Russia they

tuned in.

>> (translated): I have made a

decision.

I've been thinking about it

painfully for a long time.

Today, at the last day of the

departing century, I am

resigning.

>> I watched it on December 31.

I remember I was crying my eyes

out.

He just said, "Forgive me for

what I haven't managed to

achieve."

>> (translated): I want to ask

your forgiveness, for many of

our dreams have not come true.

(Yeltsin speaking Russian)

And for the things that seemed

easy, but turned out to be

excruciatingly difficult.

>> He gave this absolutely

heartbreaking speech.

He said that he wished that he

had done a better job by the

Russian people.

And he said, "I'm tired, and I'm

leaving."

It was... It was impossible not

to cry.

>> NARRATOR: Yeltsin's final act

as president: the father of

Russian democracy turned over

the country to his little-known

prime minister, a former KGB

officer.