By chief foreign correspondent Philip Williams.
It happened overnight.
One day Bashir al-Assad was part of the solution. An odious but necessary partner in the battle against Islamic State.
Then the gas attack in Khan Sheikhoun.
US President Donald Trump had changed his mind. A deal with the devil was no longer possible. Lines had been crossed, the regime was now going to pay.
The strike was as surgical as technology enables from a distance. Specific parts of one military airfield were destroyed.
This was a very direct act of controlled aggression with a clear note attached. Chemical weapons are out.
Use them again and expect a visit from a Tomahawk missile on your headquarters, palace, anywhere you value.
But does it in itself remove the man blamed for the atrocity at Khan Sheikhoun, President Bashar al-Assad?
If this is to be the "game-changer", the beginning of the end for the Syrian leader, it will take a lot more than a few missiles to dislodge him.