Your first comment makes little sense. Obama certainly could have spoken about Russia in the same way as Romney. At a minimum he could have not laughed at the suggestion made by Romney and made some references to Romney living in the 80s. Bottomline Obama has downplayed Russia ever since the ridiculous "reset button" incident with Hillary. Putin has had the upper hand ever since.
To your question - part of the problem is that much of the damage is done. Both Russia and Europe have learned that we (under Obama) are not going to exercise leadership. Another lead from behind situation. Given that Obama should be out
1. Making public comments about our determination and policy here. Instead he has Kerry do so. Reagan, Bush 1, Clinton and Bush 2 all were much more visible in these type situations. Obama is no where and others do the talking for him.
In addition we should be more visibly and actively involved with Europe about a unified front of policy in response. Instead we have the same old "we're right behind you" approach.
2. Will it make a difference? Probably too late. Both Russia and our allies have seen 5 years of the Obama Doctrine and at this point they'd probably just shrug it off. However, perhaps it may sow some seeds to rebuild some power for future conflicts.
3. Our interests are served by being a strong voice for and organizing force for stability on the continent and detering Putin's power grab. We can be much stronger in leadership without military force but this administration has been astounding weak in FP and the world has noticed and reacted to that weakness.