about how the U.S. got pulled so deep into Syria’s war?

The answer might be easiest to understand

if we start out small.

In March of 2016 — a series of victories in a desolate patch

of the Syrian desert.

A band of rebels captures a border crossing.

And then they move and capture a rectangular compound

that’s been in the hands of the Islamic State.

Now, like a lot of forces in Syria, big and small,

these guys want to be known.

They’d sent out promotional videos.

They’d made the TV news.

They’d even made a YouTube page,

and asked visitors to subscribe, to follow along

while they go fight ISIS.

But all these videos, they tell us something else.

American weapon.

American weapon.

American weapon.

And all this propaganda?

Behind the scenes are coalition advisers.

They’re coaching the rebels with how to introduce

themselves to the world.

They’re backing the rebels because, at the time,

this was part of America’s big plan for defeating

the Islamic State in Syria: Train and equip local rebels

to do the fighting.

“We will advise, and we will assist.”

These rebels are called the New Syrian Army.

And that compound they captured?

That rectangle in the desert?

It turned into a small military base called Al-Tanf.

That’s far away from all other

U.S. and coalition bases in Syria.

In the years to come, the base will be

attacked by ISIS,

threatened by Iranian proxies

and become the subject of Russian conspiracy theories.

This base will illustrate how

it can be easy to get involved in a war —

“This is a transnational long-term threat.”

— but much harder to get out of one.

“Senator, that would have to be provided

in a different setting.”

“Wait a minute.”

“Why can’t you — “

“Wait.

Wait a minute.”

How the mission can change in unexpected ways.

But the original mission, of course,

was to defeat the Islamic State.

The choice of Al-Tanf as a base was a good one.

Right off the bat, the rebels build a couple walls.

And this gives them control of a major road.

That lets them disrupt the Islamic State’s ability

to move between Syria and Iraq,

and to stop them from entering Jordan, which is

an important American ally.

But the rebels’ main objective is

to use Al-Tanf as a staging ground

to seize the region back from ISIS.

In their first year, the rebels have some failures —

— and they have some successes.

American and coalition soldiers

are there with them doing the training.

The rebels managed to recapture

a good amount of land, along with other rebel groups

in the area.

That’s seen in blue.

But here’s where Al-Tanf is forced

to take on an entirely new, entirely unexpected role,

an example of America’s expanding mission in Syria —

Iran.

See, when the American-backed rebels capture land from ISIS —

remember, that was their original mission —

they’re also capturing land that

President Bashar al-Assad wants back, after losing it

earlier in the civil war

that began in 2011.

So the regime’s coming after them, like it or not.

Iran’s been supporting the regime,

and has its own reasons for wanting

control of this rebel area.

See this road that Al-Tanf’s on?

It leads all the way to Iran.

Iran wants to be the dominant player in the region.

Do you think it wants a little U.S. base

blocking a valuable supply route that

carries Iranian influence and materiel all the way

to the Mediterranean?

No.

So in the spring of 2017, the Syrian army

and Iranian-backed militias decide to take

the region back with an offensive.

Their objective is to reach

the Jordanian and Iraqi borders.

In the way is Al-Tanf.

And by this time, the U.S. has established

a protective circle around the base that’s

called a deconfliction zone.

Basically, it means cross into that circle uninvited

and you risk an American attack.

But the pro-regime forces advance anyway.

The Americans strike, saying it’s in self-defense.

[explosion]

These videos claim to show the strikes on pro-regime forces.

[Arabic shouting, in reaction to blast]

Then the Americans drop leaflets warning the oncoming

forces to stay away from the deconfliction zone.

But they keep coming.

[explosion]

And the U.S. keeps striking.

And here’s where our story comes

to a pivotal moment that shows just how messy

it can be when you get involved in a civil war.

The U.S. told the world that it was in Syria

to fight the Islamic State.

“Tonight, on my orders, America’s armed forces

began strikes against ISIL targets in Syria.”

And now, it’s attacking Syrians and Iranian proxies.

“It was necessitated by offensive movement —

I don’t know there were Iranians on the ground —

but by Iranian-directed forces.”

So now we get more American hardware coming in.

Meanwhile, the base that looked like this

when the rebels took over has now grown to look like this.

But if Iran has become a factor

in the U.S. mission in Syria,

here’s an example of how the government doesn’t

want to publicly admit that this

has expanded the mission.

So let’s head to Washington for a second.

Don’t click away.

I know congressional hearings aren’t always a

thrill a minute, but this one —

“— stand.”

— gets interesting.

“So let me — so what is the — “

A senator asks a high-ranking State Department official

what U.S. troops will do in Syria once ISIS is defeated —

“ — non-ISIS priorities.”

— but question seems to strike a nerve.

“Senator, that would have to be provided

in a different setting.”

He doesn’t want to say that Iran’s part

of the Syrian strategy now.

“Um.”

“Why not?”

“Wait a minute.”

“Why can’t you — “

“Wait.

Wait a minute.

That won’t pass muster.”

So he relents, just a bit.

“We are deeply concerned with the activities of Iran,

with the ability of Iran to enhance those activities

through a greater ability to move materiel into Syria.

And I would rather leave the discussion at that point.”

The Iranian threat came just up the road from Al-Tanf.

But America’s mission in Syria is also

growing beyond ISIS because of what

lies just 12 miles to the south —

“Trapped in a no man’s land,

but still the numbers grow.”

— the lives of 50,000 refugees.

50,000.

They live in a camp called Rukban.

Many of them have fled the Syrian regime

and the Islamic State.

The camp is so close to Al-Tanf

that it’s protected by the base’s deconfliction zone.

“And we’re going to be present at Al-Tanf to make sure ISIS

cannot return and also to manage this

difficult humanitarian situation.”

Hear that?

Yet another reason to stay in Syria — protect the refugees.

But these refugees serve another purpose —

[Russian speech]

— as props for Russian misinformation.

See, Russia’s got bases in Syria, too.

It wants to secure its own influence in the region.

But the American presence in Syria, including at Al-Tanf,

is getting in the way.

So the Russians try to make the Americans and rebels

at Al-Tanf look so bad that they’ll

be forced to give it up.

[Russian speech]

They often claim that the Americans and rebels

at Al-Tanf block aid shipments to the Rukban refugees,

creating a humanitarian crisis.

But the internet is also full of conspiracy theories

about the base.

Some seem to have been influenced

by Russia’s statements.

Take Al-Tanf’s Wikipedia page.

The original entry smears the Al-Tanf rebels

by calling them armed gangs and militants that

are training terrorists, who the U.S. helps transport.

The user who wrote all this has uploaded photos elsewhere

that show a Russia connection.

How?

Well, one, they show a city Russian advisers were

in at the time.

Two, the file names are all in Russian.

And, three, one is taken from the inside

of a Russian military vehicle, like the one

seen here elsewhere in Syria.

Al-Tanf is just one example of how

Russia’s presence in Syria has contributed

to yet another reason the U.S. mission has expanded —

preventing unchecked Russian influence.

After more recent Russian threats,

the U.S. sends Marines to Al-Tanf as a show of force.

[gunfire]

The base that looked like this after those airstrikes

against pro-regime forces, has grown even bigger.

And soon after, a top general arrives,

stressing America’s support for the base.

Construction on a new expansion

begins three weeks later.

“I don’t want to be in Syria forever.

It’s sand.

And it’s death.”

President Trump reverses course,

and orders a troop pullout from Syria.

But there’s an ongoing debate in the government

about whether to make Al-Tanf the exception, to keep troops

there even after all other U.S. troops in the country

have left.

Will the base’s story end with the rebels and refugees left

to fend for themselves, or will the U.S. decide to

stay put to counter its rivals and small pockets of ISIS

in a mission that has no end in sight?

Whatever happens, remember: This is all

taking place in just one small, remote corner of Syria,

a country that’s in conflict from end to end.

So 23 seconds into this video, I mentioned

a border crossing, the one the rebels

use to cross into Syria.

Turns out, the Syrian civil war

isn’t the only time conflict touched this crossing.

I found these images from the Iraq war from 2007.

These are refugees flooding the Al-Tanf crossing,

trying to get out of Iraq.

Back then, Syria was far safer.