Russia's response to the US foray into Syria was in many ways typical of the ongoing exchange of accusations, denials and counter-accusations. But the reaction was as a whole, perhaps, a little muted, more understated than to be expected.

Russia talks a good game led by a brash, unapologetic strongman but it is also a country in a deep economic quagmire, exacerbated by sanctions. And ultimately at the crunch, a country whose military budget is approximately one-ninth that of the States even before swinging cuts due this year. 

Facing up to the new reality of the opposite corner being equally brash, equally unpredictable but, frankly, packing a lot more heat, may have just caused the Kremlin to have a moment of retrospection.