With fewer congressional seats than ever in play, the House of Representatives is splintering into hardened partisan factions. One storied group of moderate Democrats, the Blue Dog Coalition, might be counted on for bipartisanship, but after a fight over rebranding, its membership is cratering to its lowest level ever and losing its bark.

In a letter sent to President Biden and Speaker McCarthy, the Blue Dogs expressed hope for “good-faith negotiations that avoid partisan standoffs” on the debt ceiling. “Such political brinksmanship,” the group wrote, “has proven to rattle markets, damage the economy, and hurt the American people,” but they have few teeth left to sink into a solution.

The Blue Dog Coalition was formed on Valentine’s Day 1995 after Republicans took control of the House for the first time in four decades. It’s a play on the 19th century term “Yellow Dog Democrats” — loyal Southerners who would vote for a yellow dog over a Republican. “Blue dog” is credited to a Democratic congressman, Preston “Pete” Geren of Texas, who said conservatives had been “choked blue” by their party’s left wing.

In 2019, the Democratic speaker, Nancy Pelosi, attempted to bring the Blue Dogs to heel when the coalition’s co-chairwoman, Stephanie Murphy of Florida, defied the party on an immigration vote. “Decisions aren’t black or white sometimes,” Ms. Murphy told Politico, “and at the end of the day, members have to vote their districts, especially the ones, I think, who are in more vulnerable seats.”

Politico reports, “Brutal election cycles tend to decimate the Blue Dogs’ roster because the group is typically composed of swing-seat members,” but as state parties draw as many of those safe seats as possible and push gerrymandering to its legal limits, purple districts are fading from the map and moderates are disappearing with them.

In 2022, the re-election rate for House incumbents reached 94.5 percent. With odds like that, there are fewer Democratic conservatives or liberal Republicans — and less incentive for moderates to buck their party’s orthodoxy. Why cross the aisle on abortion, fiscal responsibility, or defense to cobble together legislation when it would alienate donors, activists, and a rabid dog-eat-dog base that brokers no shades of gray?

It’s a far cry from 2007, when it seemed everyone wanted to run with the Blue Dogs. In that year, Roll Call cited a congressman pf Arkansas, Michael Ross, who said “the group of fiscally conservative Democrats approved changes to its bylaws” that capped membership at 20 percent of the party caucus.

Mr. Ross, then a Blue Dog co-chairman, said the group’s “strength has always been derived from the ability of its members to reach consensus on issues put before them,” and that to “remain a cohesive and effective group, they have overwhelmingly approved new changes to their bylaws” to keep the group small.

Fast-forward to 2023 and the group has shrunk to just seven — all men — from its height of 54 members during the Obama presidency. This is the lowest membership since its founding. It was expected to be twice as large, but after a fight over sending Mr. Geren’s colorful moniker the way of Old Yeller, half the members decided to walk.

“At the core of some of the breakaway Blue Dogs’ demands,” Politico reports, “was a rechristening as the Common Sense Coalition that, they argued, would have helped shed the group’s reputation as a socially moderate, Southern ‘boys’ club,’” and which had connotations to segregationists that Democrats would just as soon erase from memory.

A co-host of the Outlaws Radio, Darvio Morrow, tweeted frustration with the demise of the group. “How stupid,” he wrote. “Democrats just blew up one of the last vestiges of their centrist past, the Blue Dog Coalition, because of political correctness. Also not surprising that of the remaining 7 members, 4 are people of color. They should take it over & grow it.”

Partisanship has rendered compromise and consensus things of the past on Capitol Hill. A few Blue Dogs will still roam the halls of Congress for the next few years seeking pats on the head from the GOP, but with their diminished numbers, the Democratic Party’s ascendent left needs no longer fear their bite.