After 6 years The conflict is divided between four sides, each side with foreign backers

and those foreign backers don't even agree with each other on who they are fighting for and who they are fighting against.

And now, Syria’s use of chemical weapons has provoked President Donald Trump to directly attack Syrian President Bashar Al Assad.

This is a major development because up until now the US has only been focused on fighting ISIS.

To understand the criss-crossing interventions and battle lines in Syria today, and how it got this way,

it helps to go back to the beginning of the conflict and watch to see how it unfolded.

The first shots in the war were fired, in March 2011, by Syrian dictator Bashar al-Assad against peaceful Arab Spring demonstrators.

In July the protesters start shooting back,

and some Syrian troops even defect from the Syrian army to join them.

They call themselves the Free Syrian Army and the uprising becomes a civil war.

Extremists from around the region and the world start traveling to Syria to join the rebels.

Now Assad actually encourages this by releasing jihadist prisoners to tinge the rebellion with extremism

and make it harder for foreign backers to support them.

In January 2012, al-Qaeda forms a new branch in Syria, Jabhat al-Nusra.

Also around that time, Syrian Kurdish groups, who had long sought autonomy take up arms and

informally secede from Assad's rule in the north.

That summer is when Syria becomes a proxy war.

Iran, Assad's most important ally, intervenes on his behalf.

By the end of 2012, Iran is sending daily cargo flights and has hundreds of officers on the ground.

At the same time, the oil-rich Arab states in the Persian Gulf begin sending money and weapons to the rebels, mainly to counter Iran’s influence.

Iran steps up its influence in turn in mid-2012 when Hezbollah, a Lebanese militia backed by Iran,

invades to fight along Assad.

In turn the Gulf states respond, Saudi Arabia really stepping up this time, to send more money and weapons to the rebels,

this time through Jordan who also opposes Assad.

By 2013, the middle east is divided between mostly Sunni powers generally supporting the rebels

and Shias generally supporting Assad.

That April, the Obama administration, horrified by Assad's atrocities and the mounting death tolls,

signs a secret order authorizing the CIA to train and equip Syrian rebels.

But the program stalls.

At the same time, The US quietly urges Arab Gulf states to stop funding extremists,

but their requests basically go ignored.

In August the Assad regime uses chemical weapons against civilians, provoking condemnation around the world.

Obama: "Men, women, children lying in

rows – killed by poison gas..."

It is in the national security interests of the United States to respond to the Assad regime's use of chemical weapons through a targeted military strike."

Russia proposed on Monday that Syria surrender control over its chemical weapons to the International

Community for its eventual dismantling, to avoid a US military strike.

The US ends up backing down, but the whole thing establishes Syria as

a great-powers dispute, with Russia backing Assad and the US opposing them.

Just weeks later, the first American CIA training and arms reach Syrian rebels,

the US is now a participant in the war.

In February 2014, something happens that transforms the war: an al-Qaeda affiliate, based mostly

in Iraq, breaks away from the group over internal disagreements.

The group calls itself the Islamic State of Iraq and Syria, or ISIS, and it becomes al-Qaeda's enemy.

ISIS mostly fights not Assad, but other rebels and Kurds,

carving out a mini-state it calls its Caliphate.

That summer, it marches across Iraq seizing territory, galvanizing the world against it.

In September, one year after US almost bombed Assad, it begins bombing ISIS.

Obama: “We're moving ahead with our campaign of airstrikes against these terrorists,

and we're prepared to take action against ISIL in Syria as well.”

That summer, in July, the Pentagon launches its own program to train Syrian rebels — but

will only train those who will fight ISIS, not Assad.

The program fizzles, showing that America now opposes ISIS more than Assad, but that

there's also no like-minded Syrian proxy forces on the ground in Syria.

In August, Turkey starts bombing Kurdish groups in Iraq and in Turkey, even as these Kurdish groups are fighting ISIS in Syria,

but Turkey doesn't bomb ISIS.

This gets to one of the big problems in this conflict: the US sees ISIS as its main enemy, but the US’s allies like

Turkey and a lot of Middle Eastern states have other priorities.

This makes for a lot of unclear confusing alliances.

The next month, in September, Russia intervenes on behalf of Assad, sending a few dozen military aircraft to a long-held Russian base in the country.

Russia says it's there to bomb ISIS, but in fact, only ends up bombing anti-Assad rebels, including some backed by the US.

The next year, Donald Trump wins the White House, vowing to stay out of Syria,

and signaling that Assad should be able to stay in power.

At the end of 2016, Assad, helped by Russian airpower and Iranian sponsored militias, retakes

the Syrian city of Aleppo, knocking the rebels out of their last remaining urban stronghold.

Then, in Spring of 2017, Assad once again uses chemical weapons against his people,

killing 85, including 20 children.

Back in the US, Trump says his attitude toward Syria and Assad has “changed very much” due to the attacks.

He vows to respond.

And within just a few days the White House launches dozens of tomahawk missiles that strike an airbase in Syria,

this is the first time the United States has directly attacked the Assad Regime.

And this adds yet another criss-crossing complication to the already multidimensional civil war.

So as it stands now Syria is in ruins.

Even as Assad recaptures land, the rebellion perseveres.

And with outside countries fueling each of the groups,

it’s clear that there is still no end in sight.