The US issued on Monday its strongest warning yet to Syrian President Bashar al-Assad: use chemical weapons in Syria's long-running conflict and we're gonna get involved.

“We have been very clear to the Assad regime but also to other players on the ground that a red line for us is, we start seeing a whole bunch of weapons moving around or being utilised,” President Obama said during an unscheduled news conference.

That very public threat was both a clear sign of how dangerous the war in Syria has become – and a reminder of the US's disastrous misadventure in Syria's neighbour to the east, Iraq.

Syria's WMDs

Not a party to the Chemical Weapons Convention, Syria has acknowledged it possesses chemical weapons – thought to include stockpiles of nerve agents such as VX and sarin gas.

The US (along with its ally – and Syria's neighbour – Israel) is concerned that the chaos in Syria could lead to the country's stockpiles finding their way into the hands of the Lebanese militant group Hezbollah or local jihadists in Syria. There's already been plenty of speculation that US special forces might play a role in securing weapons stores if Assad were to fall.

Last month Syrian foreign affairs spokesman Jihad Makdissi insisted that Syria would never turn its chemical weapons on Syrians – but might well use them against any foreign power that intervened in its 18-month rebellion.

How should we interpret these threats and counter-threats between a crumbling Syrian dictatorship and a campaigning US president? The Assad regime has employed countless forms of brutality during the country's bloody uprising. The use of chemical weapons would be a horrific but not unthinkable escalation. Of equal concern is the fear that Syria's tottering leadership could lose control of these dangerous weapons.

That said, the US doesn't have the greatest credibility when it talks about unconventional weapons in the Middle East: in the 1980s it propped up Saddam Hussein's regime in Iraq while he was actively using chemical weapons, and then 15 years later used Hussein's possession of unconventional weapons as a pretext to invade. (And, of course, there's also Israel's large, undeclared nuclear arsenal, which always seems to skirt US condemnation.)

Time to wake up

This crisis – and the very frightening possibility of an Israeli attack on Iran – should give world powers a sharp wake-up call. Only by pushing for real disarmament of WMDs can we vastly limit the damage we do to one another – not least by making interventions both less likely and, when absolutely necessary, less costly.

Learn more: To get a sense of the complexity and human scale of the Syria crisis watch and read CJ Chivers and Ben Solomon's unmissable report on the fighting in and around Aleppo.