And Russia knows darn well.

Now it comes down to whether Putin was merely beating his chest or decides to put the show on the road. It could simply mean stepping on the accelerator for all present operations in Ukraine, with an emphasis of totally knocking out all the Ukrainian command-and-control infrastructure. Kiev may bounce...

To make matters clear, he may announce that this demonstrates U.S. involvement as a belligerent, and declare that U.S. military assets in the vicinity may be targeted ad libitum. And then go quail hunting (i.e., engaging all U.S. drones over Ukarine and the Black Sea).