Back in January, when the news of the "dossier" first came out, I wrote this, essentially saying that while Russia probably did have at least a bit of dirt on Trump, Putin probably wouldn't try to use it overtly. Once you turn to explicit blackmail, you make an enemy of someone, and Trump is positively disposed towards Putin because he loves brutal dictators. If Trump were taking orders from Putin, he wouldn't have launched the missiles, which goes against the direct blackmail hypothesis at the moment, but I didn't think he was being blackmailed at the moment. My contention was that if Putin had anything, he'd leave it in his back pocket as a subtle threat, and try to remain overtly friendly to Trump. The question is, what happens now?
If Putin does have dirt on Trump, how bad is it, and what can he get for it? That determines when he uses it. Of course, there is also the possibility that he just doesn't have much of anything on Trump, and the intervention in the election was not to install a direct puppet, but just a "useful idiot" (look up the phrase, if you don't know the history). If that is the case, then the problem with a useful idiot is that second word.
However, we can treat this as a partial hypothesis test of the blackmail hypothesis test. If things go too sour with Russia, then Trump isn't being blackmailed. We all might glow in the dark, but hey! Our President isn't compromised! If everything calms down, then things are less clear. It could be that Putin dangled blackmail threats in front of Trump, or it could be that some clear-headed advisor (Mattis, maybe) pointed out that a full-blown war in Syria has a lot of downside risks that Trump might not be willing to take.
So, maybe we'll find out what the deal is with Trump and Putin. Hopefully with minimal casualties.