John McCain has famously said that he would rather lose an election than lose a war. He seemingly sacrificed his Presidential ambitions in favor of our national interest.
In Barack Obama, it seems that we have the converse. He had declared the war lost and withdrawal an imperative when it was politically expedient. Now it seems that the reality on the ground (both polling in the US and the security in Iraq, in that order) has shifted, and Barack Obama is about to change his position.
Where John McCain put the war above his election, Barack Obama puts the election above the war, and everything else.
The lesson here is that Barack Obama is willing to sacrifice anything and everything for his political ambitions. No friend is too close, no promise so (seemingly) heartfelt, no principle so great will get in the way of his election.
Now there is a contrast with John McCain.