With the Maryland primary on July 19, through mid-September, 20 states that have a total of 155 congressional districts will hold their U.S. House nominating contests.
Eight incumbents—among them five Republicans and three Democrats—have been defeated in primary elections so far this year. Half of those were in situations where two incumbents were forced to compete in a primary due to redistricting.
It is rare for incumbents to lose renomination because they tend to have advantages in terms of fundraising and name recognition but primaries can be stratified by ideological deviations ranging from the subtle to the extreme.
Among Republicans, there has been a divide since 2010 between the establishment wing of the GOP and the more extreme Tea Party, which has morphed into a cult-like following for disgraced former President Donald Trump, the 2020 election loser who sought to hold on to power through an illegal and violence coup d’etat.
Democrats have similar internal divisions, although most anti-establishment candidates have failed to garner traction and suffered from rampant disorganization as well as progressive
At the most basic level, dissension on the left has split mainstream liberals off from left-wing proponents of the democratic socialism espoused by the likes of Bernie Sanders.
Alexandria Ocasio Cortez’s upset of top Democrat Joe Crowley in the 2018 NY-14 primary encapsulates the rancorous juxtaposition of these two differing camps well.
Few insurgents are successful and seldom do candidates from one party unseat incumbents of the other since political insiders generally cheat by drawing districts that are not competitive.
In addition, incumbents have an incredible financial advantage over most challengers because the people’s representatives and senators have failed to address the problem of money in politics, which operates as a system of legal bribery.
There are 187 Democratic-leaning congressional districts, 208 House seats that are leaning Republican and only 40 highly competitive seats in the new maps.