China has been moved to assemble troops on its border with North Korea, though for what purpose was unclear yesterday. Trump had earlier tweeted that he had "explained to the President of China its trade deal with the US would be better if it solved the North Korean problem" but it is unlikely China would bring North Korea to heel for a trade deal.
All that can be said with certainty is that Trump is finding foreign policy a great deal more satisfying than domestic affairs.
The Syrian strike brought him a chorus of support at home and abroad, which would have been a pleasant change after his failures to put a new healthcare bill through Congress and get restrictions on Muslim immigration through the courts.
The military might at his command is far more responsive to his wish. Experienced politicians come to the US presidency knowing the office is severely constrained by constitutional checks and balances at home and has more latitude to act abroad.
Trump will be learning as he goes.
It is encouraging to recall that amid all his self-confident bluster on the election campaign he always declared a high regard for military advice.
For every enemy he resolved to defeat, the generals, he said, would come up with a terrific plan.
After the Syrian gas attack, they gave him a "proportionate response", meaning it was calculated not to escalate the conflict, certainly not with Russia. A warning was given, casualties were minimised, the airfield was not even put out of action.
But the necessary message was given that poison gas is not an acceptable weapon of war.
Likewise, there is reason to be confident the US Joint Chiefs are treating North Korea with caution so the President can put China to a test.
North Korea's nuclear programme is a response to its leaders' fear, whether real or feigned for propaganda, that the US threatens its existence.
Trump needs to be careful not to play the part its propagandists write for their misled people.
