The Blue Dog Coalition took a hit on Tuesday when two Pennsylvania centrists – Reps. Tim Holden and Jason Altmire – fell to primary opponents. The losses will further erode the influence of the group, which saw its membership fall from 54 to 25 over the past two years. And the decline is likely to continue in the next Congress, as a number of Blue Dogs are retiring at the end of 2012.

The trend has led to concerns from some Democrats – and accusations from some Republicans – that House Democrats have swung far to the left and lost their ability to relate to conservatives across the aisle.

But Rep. Xavier BecerraXavier BecerraThe Hill's 12:30 Report: Trump's pre-debate COVID-19 test sparks criticism Biden unveils updated strategy to end HIV epidemic by 2030 Buttigieg has high name recognition, favorability rating in Biden Cabinet: survey MORE (Calif.), vice-chairman of the Democratic Caucus, rejected that notion Wednesday, arguing that, despite some changing tides, House Democrats still span ideology and ethnicity in ways other bodies within Congress do not.

"You will see every shade [and] corner of America represented in the Democratic Caucus," Becerra said. "And we take great pride in that.

"The complexion of the House Democratic Caucus may change a bit," he added, "but I don't think there's any doubt that the House Democratic Caucus is the most diverse body of legislative representatives you can find at the federal level of the United States."

The Democrats said they're confident the party will ultimately win the districts Holden and Altmire were vying for, and noted that Republican incumbents have also had their share of tough primary races this year.

"At the end of the day, we all service at the pleasure of the people and the voters," Becerra said.