But Sanders' potential impact extends beyond the presidential race. A plurality of voters, 39 percent, say they will be less likely to vote for a Democrat for Congress if Sanders is the Democratic nominee and his ideas are folded into the party platform. That's nearly double the 21 percent who say they would be more likely to vote for a Democrat for Congress, while 34 percent say it wouldn’t impact their vote.

A separate memo drafted for Bloomberg’s campaign by the polling firm and also obtained by POLITICO claims “Sanders jeopardizes [the] Democratic majority in House” but doesn’t outright argue Democrats would lose the House if Sanders were the nominee.

The poll found that 47 percent of voters in competitive, Democratic-held districts felt that “the increased role of socialist ideas in the Democratic Party” was a “bad thing,” and 19 percent “ believe it is a good thing,” and 24 percent said “it makes no difference to them.” The poll was conducted Feb. 22-23 and surveyed 600 likely general election voters across 42 districts in the Democratic Congressional Campaign Committee's "Frontline" program for vulnerable party incumbents. The survey's margin of error is plus or minus 4 percentage points.

Sanders has come under more sustained scrutiny since becoming the frontrunner in the race. On Monday, Joe Biden’s campaign began airing a new digital ad accusing him of working to undermine former President Barack Obama’s reelection by threatening a primary. Pete Buttigieg is on the air in South Carolina criticizing Sanders’ plan to eliminate private health insurance. Sanders’ past gun votes were the subject of an online video by Bloomberg, who argues the Vermont senator is too divisive to beat Trump. Senior Bloomberg officials renewed warnings on a call with reporters on Monday, arguing that a candidate with even a small plurality of votes in upcoming contests can come away with an outsize and disproportionate delegate lead.

The memo and four-page section of the survey was conducted over this past weekend — as Sanders was winning convincingly in Saturday's Nevada caucuses — and comes as the progressive frontrunner prepares for more big delegate hauls on Super Tuesday.

Weekly Score Your guide to the year-round campaign cycle. Sign Up Loading By signing up you agree to receive email newsletters or alerts from POLITICO. You can unsubscribe at any time. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

The memo was shared with some House Democrats late Monday, including members in vulnerable House districts. Bloomberg’s House supporters received a briefing on the results, a source said, which are also being used to recruit new endorsers as Sanders rises and Biden’s candidacy largely hinges on the outcome of South Carolina’s primary this Saturday.

In recent weeks, members of Bloomberg’s campaign have traveled to Washington to brief groups of House Democrats, raising alarms for moderates if they don’t quickly consolidate support that is currently spread across multiple candidates and what that scenario means for delegates awarded on Super Tuesday. Bloomberg’s campaign has briefed both Senate and House staff and lawmakers on the volume of early votes already being cast in Texas and California, according to a source.

The campaign has also shared data and information on their Hawkfish project, billed as a startup meant to create data and tech infrastructure for Democrats, with the Congressional Black Caucus.

Bloomberg has aggressively courted House Democrats, including some members who have endorsed other candidates. He’s shopped himself as a moderate alternative to Biden and is privately courting Democratic officials and members to swing their support to him in preparation for a possible brokered convention should Sanders win a plurality but fail to meet the threshold of needed delegates.