For the Prime Minister, the successful return of British service personnel and confirmation of no Russian casualties will be the main source of relief this morning.
Even supportive MPs said she was in an “impossible position” squeezed by the need to act, but the absolute need not to escalate tension with Russia too much.
On the international stage, Number 10 will believe that Syria and Russia have been sent a clear and unambiguous message about use of chemical weapons, but no serious conflagration with Russia need arise from events overnight.
The White House under Donald Trump has been given an incentive to work with G7 partners too, which did not happen a year ago, and might be important in future.
At the Downing Street lectern, the PM’s demeanour seemed far more in keeping with the “one shot”, one-off strategy outlined by US defence secretary Jim Mattis than anything more prolonged.
This was not about intervening in the Syrian civil war, nor about regime change, she said repeatedly.
But that does open up the most potent of domestic concerns from her own MPs – that this was “gesture bombing” – a kind of evolved form of “liking” one of President Trump’s bellicose tweets, except with missiles rather than mobile phone apps.
If the PM seemed somewhat hesitant in her Downing Street address after British participation in the airstrikes on Syria, then that is in keeping with where the country is on this.
As she mentioned – this is the first time she has officially sanctioned military intervention as PM. And this is why, although relieved at the international and military response, the domestic response to having ended the recent convention on seeking Parliament’s approval may be more troublesome.
On the one hand, some Conservative MP sceptics of action in 2013 – such as Crispin Blunt and Sarah Wollaston – have publicly backed the PM. The DUP too was very supportive.
Others were clear that this should have gone to Parliament, where she probably has a majority for this but could not be absolutely sure.
The PM was at her most hesitant in explaining why it did not go to Parliament.
Legally, she does not have to under prerogative powers, as she referred to herself.
But there clearly was time to recall Parliament last week, as Ken Clarke has said.
Mrs May did not have a clear answer to why the action could not have waited until after the Office for the Prohibition of Chemical Weapons visits Syria on Saturday to assess the Douma attack.
She said it was “not simply about Douma” but about a “wider pattern” – and it was “important that at the point at which we had the information that showed us that all the indications were this was Syrian regime, that we took action necessary”.
The timing “gave a clear message” to Bashar al Assad, she said, implying that the message would have been palpably murkier if delivered on Monday or Tuesday.
Jeremy Corbyn senses a public sceptical of intervention. Even Vince Cable, who appeared ready to lend support to the PM, criticised the failure to get parliamentary approval.
Both leaders said the PM preferred to follow Donald Trump than seek approval from MPs.
Some MPs will suspect too that there are those in the White House who have Donald Trump’s ear, who might want want to push for a stronger, harder, more prolonged form of military action in the next few months.
Would MPs get a vote in UK participation in that situation? Or is the relatively recent convention now forever banished?
Parliament will discuss this on Monday. The geopolitical fallout is limited. But the domestic political precedent on who decides war, at a time of low trust in politicians and experts, matters hugely.