Herod, if they are places like Crimea or Eastern Ukraine which are historically part of Russia then let him have them.
75% of the population in Eastern Ukraine do not want to be part of Russia or some other 'independent' state.
The 'pro-Russia rebels' are mainly Russian citizens, as the body count of Russian dead at the airport attack attests.
The leader of the Russian insurgents has admitted they are mostly Russia fighters, he justifies by saying that part of Russia has always been Russian, not Ukraine.
There is no sign of American involvement, weapons or dead. If they were involved you'd expect a lot more success...