The end of income compression has been credited to "impersonal forces", such as technological change and globalization, but also to political and policy changes that affected institutions (e.g., unions) and norms (e.g., acceptable executive pay). Krugman argues that the rise of "movement conservatism"—a "highly cohesive set of interlocking institutions that brought Ronald Reagan and Newt Gingrich to power"—beginning in the late 1970s and early 1980s brought lower taxes on the rich and significant holes in the social safety net.