As the current political narrative has it, President Barack Obama has been weakened by the midterm elections. So it should come as no surprise that his failure to sell Congress' version of the U.S.-South Korea free trade agreement is a reflection of Obama's weakened position, rather than, say, a reflection of Congress' unrealistic expectations of what trade concessions other countries are willing to make in the current dismal economic environment. The same latent theme runs through much of the coverage of Obama's tepid performance at the G-20 summit, although it is not as pronounced.
So be it, narratives are often as revealing as they are misleading. And there's no question that Obama has been weakened by both the midterm elections and how they are perceived abroad.
But there are other reasons for why he is struggling to convince most of the world's major economies to sacrifice their own interests in favor of America's. Some are structural/political, while others are ideological/cultural. Everyone knows that sacrifices are necessary to restore balance to the global economy, but everyone wants to outsource the political pain. There are also fundamental differences of opinion about the best way to restore that balance, having to do with economic biases due to divergent national cultures and histories.