Obviously George W. is the correct answer. Russia didn't invade sovereign nations when Bush was president.
Can't tell if this is sarcasm or you don't recall the
invasion of Georgia by Russian forces in 2008. If it's the former, I apologize for not being able to detect your sarcasm on the Internet.
As to the question itself, I can't tell much of a difference between the two when it comes to foreign policy prerogatives. Obama still accepts the War on Terror as legitimate and still uses it as a foil by which to expand U.S. operations in the Middle East. He just does it in a way that is less brazen and focuses more on bringing the rest of the West onboard with it, rather than alienating everyone and confronting regimes targeted for destruction head on. I would say that on the whole a case could be made for Bush having at least a slightly better foreign policy in that he mangled the entire thing and made the US less respected and weaker abroad, thus sabotaging most real efforts at settling accounts in the Middle East in the favor of the United States. Plus, Bush at least made it possible for a liberal opposition to at least condemn his actions rhetorically and act against them in a limited fashion, thereby limiting his overall ability to implement his designs for the Middle East.
With Obama, liberals bend over backwards to support whatever imperialist project proposed by the administration, and conservatives really only condemn these insofar as they are not aggressive enough. This makes the Obama administration's foreign policy far more dangerous, as it can get a blank check for whatever it is it wants to do from liberals while not having to worry about any serious opposition.