Members of Congress have raised fears that Bernie Sanders could cost Democrats control of the House of Representatives if he is selected as the party’s US presidential nominee.

House speaker Nancy Pelosi batted away reporters’ queries about whether it is time for her to try thwarting Mr Sanders to protect her party’s majority in the lower chamber of the US legislature.

She said: “We’re not going to lose the House. We’re going to be united by whomever is the candidate for president. But we are taking responsibility for winning the House, and we’re not assuming anything. But we feel very confident.”

House speaker Nancy Pelosi
House speaker Nancy Pelosi (J. Scott ApplewhiteAP)

She delivered a similar message to colleagues at a closed-door meeting on Wednesday morning, when she told them: “We cannot show any division. This has to be about unity, unity, unity.”

Yet with Vermont senator Mr Sanders riding high in the race to become the Democrats’ presidential candidate after early nominating contest wins in New Hampshire and Nevada and a virtual first-place tie in Iowa, other House Democrats were less relaxed.

Time is running out to head Mr Sanders off. South Carolina holds its primary on Saturday, followed three days later by Super Tuesday, when contests in 14 states and one territory will decide a third of the delegates to this summer’s Democratic convention.

Representative Tom Malinowski, a new member of Congress from a closely divided New Jersey district, said Democrats have “a simple path” to defeating US President Donald Trump by focusing on healthcare, the economy and a promise that their presidential candidate will not lie. In an unspoken reference to Mr Sanders he said he does not want to “squander that opportunity” by nominating a contender who divides Democrats.

Bernie Sanders
Bernie Sanders won the New Hampshire primary and Nevada caucus (AP/Gerald Herbert)

Representative Elaine Luria, who defeated an incumbent Republican in 2018 in a swing district in coastal Virginia, said a Sanders candidacy would be “incredibly divisive” and endanger more centrist politicians like herself. The former Navy commander said of Republican efforts to paint all Democrats as socialists: “Bernie Sanders just adds fuel to that fire.”

Representative Scott Peters, a leader of his party’s House moderates, said there is widespread concern among members of Congress from competitive districts “that a Sanders candidacy would sink their re-elections”.

Mr Peters, whose San Diego district is safely Democratic, said Mr Sanders would complicate moderates’ re-election bids because “the face of the Democratic Party might be spouting things that are absolutely anathema to your voters”. Mr Sanders’ position on “Medicare for All”, the Green New Deal and student loans has alienated many moderates.

Of the 42 House seats Democrats gained in the 2018 mid-term elections when they captured the majority, 29 are from districts that Mr Trump either won in 2016 or lost by a narrow 5 percentage points or less. Most of them are moderates.

Republicans will need to gain 18 seats in November’s elections to win House control, assuming they retain three vacant seats that they previously held.