Is there a direct link between what US President Donald Trump says and what Russian President Vladimir Putin does? Certainly, the harsh words and bitter violence of recent days in Ukraine suggest the answer is maybe.

Any analysis of Donald Trump's current thinking on Russia risks getting out of date very quickly.Read too much into an individual tweet, post or off-the-cuff comment by the US president, and the danger is that your conclusions will be contradicted by tomorrow's tweet,

The Russian leader is convinced that Moscow’s battlefield superiority is growing, and that Ukraine’s defenses may collapse in the coming months, according to people close to the Kremlin.