NO DOUBT Donald Trump was keen to emphasise his decisiveness, in contrast with his predecessor’s dithering. There were hints earlier in the week that the president was thinking of doing something. After a nerve-gas attack by the Syrian air force killed more than 85 people in the rebel-held town of Khan Sheikhoun on April 4th, he said that Bashar al-Assad, the Syrian dictator, had crossed “many, many red lines”. In the early hours of April 7th, Mr Trump took action.

American ships fired 59 cruise missiles at the al-Shayrat airfield, from which planes carrying the chemical bombs are believed to have taken off. The strike was limited and targeted. Even so it debunked the idea that the use of any kind of force in response to the barbaric behaviour of the Assad regime was no longer possible because of fears that it would mean confrontation with his Russian ally, which has been operating in Syria since September 2015. The Russians were informed of the strike in advance, but they were not, apparently, consulted over it. It is not clear whether any Russians would have been at the base. But the warning, doubtless passed on to the Syrians, seems to have given the latter enough time to evacuate at least some of their planes. In military terms, therefore, the operation will make little difference to the Assad regime’s capabilities. 

Mr Trump will rightly win praise for his willingness to make more than a hand-wringing statement about the Syrian regime’s flouting both of international norms and its own obligations since becoming a reluctant signatory in 2013 of the convention against the use of chemical weapons, following its last major outrage of this kind. In the past, Mr Trump has appeared indifferent to the idea of humanitarian intervention. But faced with such a vile and provocative act perpetrated on his watch, he asked his generals for an appropriate response, which they provided. The professional national-security team that he now has in place in the shape of his defence secretary, James Mattis, and his national security adviser, H.R. McMaster, deserves credit for this, but the final decision was of course the president’s.

Many Obama-era officials will regret that their own administration did not do something similar. Mr Obama still maintains that he is proud of the agreement struck with Russia in 2013, following a much more serious attack, to strip Mr Assad of his chemical weapons in return for calling off the air strikes that Mr Obama had previously threatened. It is now clear that even despite the best efforts of weapons inspectors, Mr Assad hid some of his huge chemical arsenal with the intention of deploying it again when he thought he could get away with it. 

The question now is what happens next. Rex Tillerson, Mr Trump’s hitherto almost invisible secretary of state, is due to meet Russia’s president, Vladimir Putin, in Moscow next week. Mr Tillerson has accused Russia of either being “complicit” in the attack or “incompetent” in its inability to restrain its ally. Only a few days ago, Mr Trump’s officials were signalling that it was no longer an aim of the administration to remove Mr Assad from power as a prerequisite for a deal to end the war in Syria, which has claimed perhaps half a million lives. Has Mr Trump changed his mind? Or, having slapped Mr Assad on the wrist and warned the Russians that he cannot act with impunity, will America continue to stand back from the peace negotiations? Confusingly, Mr Tillerson said, after the attack, that policy toward Syria has not changed.

There are other uncertainties too. Even if Mr Assad forsakes chemical weapons but continues to drop barrel bombs on civilians, will Mr Trump want to stop him or will that be as permissible as it was only a few days ago? If the former, what are the risks of escalation that could lead to a much bigger confrontation with Russia and Mr Assad’s other ally, Iran, especially if military escalation slips into having regime change as its objective? So far, there is no indication that the cruise-missile attack will be anything more than a one-off, but that, of course, could change.

Either way, the prospects of co-operation with Moscow in the campaign against Islamic State in Syria that Mr Trump was once so keen on were already slim and are now probably doomed. Will that make it harder for America and its allies to complete the job of expelling IS from its “capital” Raqqa and elsewhere in Syria? Is there now a greater danger that Iranian-backed Shia militias in Iraq, fighting more or less alongside Americans in the battle to retake Mosul, will at some point be turned against them?

It will also be interesting to see what this means for the wider relationship with Russia that Mr Trump was once so keen to develop. The Russian response to the missile strike will be telling. The initial reaction from the Kremlin was to brand the American action as a violation of international law, but Mr Putin the pragmatist may decide that nothing further needs to be done. In warning Russia of the attack, some agreement may already have been forged, particularly if Mr Putin indicated a readiness to constrain Mr Assad in the future. Despite Mr Tillerson’s harsh tone in describing Russia’s role, Mr Trump has been milder, describing the chemical attack as a “very sad day for Russia”.

At home, Mr Trump will almost certainly see at least short-term benefits. The speedy way the action was carried out creates a counter-narrative to the picture of muddle and confusion his administration usually presents, particularly in the recent debacle over health care. The president’s willingness to risk a confrontation with Russia may, for a while, take a little of the heat out the speculation that Mr Trump is in some way compromised by the Kremlin or in its debt. Republican hawks, such as Senator John McCain, who have been appalled both by America’s passivity over Syria and Mr Trump’s chumminess towards Mr Putin, may now see him in a new and more flattering light. So might some Democrats.

Whatever else, Mr Trump has demonstrated his capacity to surprise.