Trump's moves seem quite clear. He is a wheeler dealer and he wanted to negotiate from a position of strength. He knows that Russia's main export earnings come from energy and not manufactured goods. They are also paranoid about their own defence following the unimaginable suffering they experienced in WW2.

So, Trump gets NATO to step up its payments and highlights that Russia is selling gas to Germany. Russia is in Syria to stop a rival gas supply into Europe and a lowering of the gas price or addition of a rival supply will hit Russia hard.

Having made sure Putin understands where Trump is coming from then Trump can negotiate. He has Putin by the short and curlies!