Carville can relax - members of Congress are probably safe as houses

Depending on what wing of the Democratic Party you belong to, Zohran Mamdani’s victory in the Democratic primary for mayor of New York City last week was either a warning shot or a cautionary tale. In picking the 33-year-old state assemblyman and self-described democratic socialist, Democratic voters dealt a stinging rebuke to the party establishment. That, in turn, has led to plenty of chatter that incumbent Democratic members of Congress could be vulnerable in their own primaries next year.

But we should be cautious about drawing conclusions based on a single election, especially one as unique as the New York City mayoral race. The issues and demographics of the country’s largest city are pretty different from those of most congressional districts. And Mamdani’s main opponent, former New York Gov. Andrew Cuomo, was a very flawed candidate (he resigned from office in the face of several sexual-harassment allegations, and he also faced criticism for his handling of COVID-19 in nursing homes). 

So we probably shouldn’t expect an unusual number of incumbents to go down in primaries next year. However, that doesn’t mean that the Democratic Party establishment can rest easy. The relatively high level of Democratic discontent could still manifest itself in open-seat races. The biggest impact of the Tea Party movement wasn’t incumbents losing primaries, but rather the proliferation of a new breed of uncompromising, anti-establishment conservatives that moved the Republican caucus right, obstructed legislation favored by GOP leadership, and ousted multiple speakers of the House. Similarly, MAGA-aligned legislators have displaced old-guard Republicans in Washington since President Donald Trump’s first election in 2016, predominantly not through defeating them in primaries, but succeeding them after they retired. Over on the Democratic side, most “Squad” members other than Ocasio-Cortez and Pressley — including Rashida Tlaib, Ilhan Omar, and Summer Lee — were first elected from open seats. And, of course, last week’s Democratic primary for mayor of New York City didn’t feature an incumbent either.

Simply because of the sheer number of open seats (18 representatives have already retired or resigned this year, and the average cycle since 2009-10 has seen 52 representatives do so), one of the biggest things to watch for in the 2026 congressional primaries will be whether Democratic primary voters nominate more candidates opposed by party leadership. (Some more grist for this theory: Another CNN poll from April found that Democrats disapproved of the way Democratic leaders in Congress were handling their jobs, 57 percent to 42 percent. That’s much more overtly negative than their views of the party in general.) And if those candidates go on to win the general election, Democratic leaders in Congress could experience for themselves the same kind of intraparty strife that has plagued Republicans in recent years.

But history suggests that sitting Democratic members of Congress are in no special danger in 2026 primaries. Even in the most anti-incumbent election cycles, 95 percent or more of incumbents still win renomination.