:: Why now?
Donald Trump acted swiftly– within 80 hours of the chemical weapons attack in Idlib province.
We’re told by the White House that he was deeply affected by the images of dead and dying children and it was a very personal decision to strike Syria. They say you only know true pressure once you lead a country.
Maybe this was the moment Mr Trump truly realised the power and responsibility he has, as leader of the world’s only superpower.
There was also a political advantage in acting so swiftly. His decision to strike Syria will be compared to Barack Obama’s decision not to, and Trump will hope, probably quite realistically, that he will be judged favourably for it.
And, on the eve of talks with the Chinese president at his Florida residence, Mr Trump is showing that he isn’t afraid to order military action – that will be very evident when the two sit down to talk about North Korea.
:: What will Russia do?
Russia was given notice that the attacks were about to happen, although we don’t know how much notice.
Theoretically, they could have shot down some of the missiles using their advanced surface-to-air defences that they have strategically positioned inside Syria. But they didn’t.
Russia will need to respond so as not to lose face, but I have no reason to believe Moscow wants a conflict with Washington any more than vice versa.
Russia’s response will probably come in the form of strong words of condemnation, through press statements and an appearance at the UN Security Council. They have suspended a deal with the US to prevent mid-air collisions over Syria in response to the strike.
They could also move more troops or military assets into Syria to show support for Bashar al Assad and strengthen their position in the country. Privately, they might warn Assad he stepped over the line this time, and they won’t protect him if he does it again.
:: What was Britain’s involvement?
The British Government, as America’s close ally, was told about the strikes yesterday.
Michael Fallon was phoned twice by his counterpart, General James Mattis, the second time just after midnight, to confirm the strikes had been authorised.
But Britain wasn’t asked to contribute. Even if it was, the Government would have needed Parliament’s approval before acting. As things stand today, I don’t see that happening.
:: Will it change the course of the Syrian war?
Unfortunately, I doubt it.
Images of women and children bombed daily in eastern Aleppo didn’t encourage US intervention or change the course of the conflict.
The world will move on and largely forget, and with it the political impetus to do anything will fade away.
The exception of course is if Assad uses chemical weapons again and then Mr Trump, having acted already, will be forced to do so again, with greater strength and probably decisively.
:: What next?
All the signals suggest this was a one-off strike, punishment for Assad for using chemical weapons and a warning not to do it again.
If there was a wider intent to remove Assad from power, for example, then you would expect sustained missile attacks aimed at a diverse list of targets: command and control centres, government ministries, military installations.
But Mr Trump has laid down a marker now and he must commit to it and he will be judged by it. How this all pans out will likely be decided by the response from Russia and Syria.