Sorry to say, but no. America has declined in it's military power over the years, but it's still more than powerful enough to handle Russia. The only REAL threat I see that America would currently ever have is China.
America would never start a war with Russia or any other country that got long-range missiles. The only reason why USA is not backing down from countries like Irak, Afghanistan and Syria is because they can't harm American citizens, the frontline is far way. Now if Russia and USA would have a war (god forbid), Russia would just bomb the hell out of NewYork, Washington, Chicago basically any city with economical or political vallue.
The moral and endurance of the normal citizens determine the winner, judging from 9/11 and the fact that America haven't had a war in a very long time, I would say that Russia folks can handle more
