此外，奥巴马还面临了重大约束，包括全球经济危机、国内政治两极分化、敌意国会，以及需要美国又不愿接受美国主导的新兴大国的崛起。
Moreover, Obama has been confronted with significant constraints, including the global economic crisis, domestic political polarization, a hostile Congress, and the rise of emerging powers that need the US but are unwilling to accept its dominance.