At his inauguration, President Barack Obama was seemingly poised to become America's strongest and most influential president since Ronald Reagan. However, President Obama's first two years in office has led to some notable surprises. What accounts for the political stability and change demonstrated by the Obama administration? Which factors shaping a presidency are structural, which are personal, and which are driven by events? How will decisions made in the first two years of the administration affect its future course? What lessons can we glean from past presidencies?