General Discussion

"As conservative plutocrats gained greater power, what had been a relatively mainstream conservative party came to embrace positions far to the right of both its historical stances and the positions of conservative parties abroad. Nowhere is this clearer than in economic policy. Political scientists have developed rigorous measures of the ideological position of elected officials based on roll-call votes in Congress. According to these indicators, the cleavage between the parties centers on economic issues, such as tax policy, regulation, and the size of government. These indicators show that Republicans became sharply more conservative in the 1990s, 2000s, and 2010s. Over this same period, no comparable leftward movement can be seen among Democrats.

"Polarization, in other words, has become 'asymmetric.' According to one widely used measure ... about one in five congressional Republicans and a similar share of congressional Democrats were 'ideologically extreme' according to their left-right voting patterns in 1990. By 2000, three in five of Republican members of Congress, were, with no change in the Democratic share. A decade on, more than four in five Republicans in Congress were -- again, without any parallel movement among Democrats in Congress."

Jacob S. Hacker and Paul Pierson, "Let Them Eat Tweets"