Russia—no matter who’s leading it—either wants the Ukraine and the ‘stans (Kazakhstan, etc.) back; or else at least doesn’t want them under the control of a foreign block.
Foreign blocks (read: USA, EU) want to keep Russia out, so as to be kept weak (and expand on the “New World Order” idea).
It’s the Great Game, just being played all over again.
Putin isn’t Hitler; his successors will have the same goals;
and Cameron’s “... there’s a different and better way for Russia to behave that could lead to an easing of relation...”
is simply ignorance of the reality of Russian interests,
which will propel Russia’s actions.
Even the Germans are fed up with Putin's bull----, and Obama will be in office just two more years.
Putin is a fool picking a fight with a US and Europe that combined have almost 10 times his population and 20 times his GDP-- it's like having your ankles bitten by a nasty terrier. Meanwhile Chinese immigrants pour into the Russian Far East.