Putin will not invade Poland. He will not because Russia has no cash to support an invasiin and Poland is a member of NATO and if his army steps foot in Poland, he will get nuked or every member of NATO would be occupying Moscow in a matter of weeks.
We have made the same mistake with Russia after Cold War I, as we did with Germany after World War I. Only this time the Hitler has nukes.
Your contention is that Obama would launch a nuclear first strike on Russia?
They always go after poland. Nato is weak. Obama will dither. Kerry will bluster. But not fight. Without us taking the lead, europe will do the same. The public has no apitite for war here or in europe. Poland will bit by bit be annexxed.