Conversely, leftist leaders who arise from a populist, purely nationalist past, with few ideological underpinnings – Chávez with his military background, Kirchner with his Peronist roots, and Mexico City mayor and presidential frontrunner Lopez Obrador, with his origins in the Institutional Revolutionary Party – has proven much less responsive to modernizing influences. For them, rhetoric is more important than substance and power is more important than how it is exercised.