As Sanders builds what could eventually be an insurmountable delegate lead, many Democratic House and Senate candidates are approaching a dramatic shift in their campaigns, as they recalibrate to include praise of capitalism and distance themselves from the national party. Top campaign strategists from both parties view Sanders’s success as a potentially tectonic event, which could narrow the party’s already slim hopes of retaking the Senate majority and fuel GOP dreams of reclaiming the House, which it lost amid a Democratic romp in 2018.

“I can tell you that there are a lot of down-ballot jitters based on my conversations with my former colleagues,” said former Rep. Steve Israel (D-N.Y.), a longtime confidant of House Speaker Nancy Pelosi who led congressional election efforts from 2011 to 2015.

“Donald Trump is going to offer the American people this choice: Do you want to continue building the economy or do you want to lurch toward socialism? And that is a real powerful argument in the Democratic districts that Trump won in 2016.”