In October 2015, John Boehner was driven from office by right-wing members of his own caucus. His successor, Paul Ryan, despite having been chosen as the Republicans’ 2012 vice-presidential nominee based on his ideological bona fides, faced similar pressure from his right as speaker — ultimately deciding to spend only three years in the role before announcing his resignation from the House last week.



Meanwhile, Nancy Pelosi, the minority leader, is still leading her caucus despite losing her party’s majority nearly eight years ago.

Since the election of Donald Trump, political analysts have expected a left-wing version of the Tea Party movement to arise. But Republicans still suffer from more ideological dissension even after gaining control of Washington.

As the 2018 nomination season gets underway, analysts anticipate a network of insurgent candidates and activists to seek a liberal purification of the Democratic Party, in the same way that Tea Party members took aim at a detested Republican “establishment” via a series of formidable primary challenges and congressional leadership battles. Yet there has been no evidence of a national, ideologically motivated rebellion among Democratic primary voters, interest groups or donors.