There seem quite some influential people in the US, who would be willing to order the defense of Georgia and Ukraine, if they could get them into NATO. As I interprete Marek's comments, Poland would act as well, because they would see an agression of Russia against Georgia or Ukraine as a possible prelude to an attack of Poland.

As for your last paragraph, with US backing, eastern Europeans are not THAT small, that they would have to go along with everything Russia does.

Der Amerikaner ist die Orchidee unter den Menschen
Volker Pispers