Republicans are making Michigan Senate nominee Abdul El-Sayed the centrepiece of their campaign against the Democratic left, betting that warnings about socialism will help them defend narrow congressional majorities in November.

President Donald Trump called El-Sayed a “Communist loser” after his primary victory and accused him, without providing evidence, of hating Jewish people. El-Sayed has repeatedly condemned antisemitism and said opposition to Israeli government policy should not be equated with hostility towards Jews.

The political labels are not interchangeable. Democratic socialism pursues greater public control and expanded social programmes through democratic elections, while communism traditionally seeks to abolish private property. El-Sayed is not a member of the Democratic Socialists of America and describes himself as a progressive rather than a socialist or communist.

Trump intensified the personal nature of his attacks on 8 August by sharing photographs of himself and Melania Trump alongside El-Sayed and his wife, Dr Sarah Jukaku, under the caption “Two VERY DIFFERENT America’s [sic]”.

Asked about the post on CNN, El-Sayed replied: “Yeah, he’s right,” before presenting the contest as a choice between an administration benefiting wealthy interests and one focused on families and living costs.

El-Sayed, a 41-year-old doctor and former public health official, narrowly defeated establishment-backed Representative Haley Stevens in Michigan’s Democratic primary. When the Associated Press called the race, he was leading by 14,893 votes — just under one percentage point — from more than 1.5 million ballots.

He will face Republican former congressman Mike Rogers in November for the seat being vacated by Senator Gary Peters. The result could help determine control of the Senate. El-Sayed would become the chamber’s first Muslim member if elected.

His campaign concentrated on universal healthcare, reducing corporate influence in politics, ending unconditional US military assistance to Israel and abolishing Immigration and Customs Enforcement.

National Republicans have sought to use those positions to portray the wider Democratic Party as moving sharply left. Trump and House Speaker Mike Johnson have repeatedly described progressive candidates as communists, despite several of their targets not identifying as democratic socialists.

The strategy has not won uniform support among Republican campaigns. Reuters interviewed advisers to 11 candidates in competitive House races and found five were embracing the socialism argument, while six considered it secondary or doubted it would outweigh voters’ concerns about prices.

Public opinion also presents a more complicated picture. A Reuters/Ipsos survey of 1,097 registered independents found 64% supported raising taxes on corporations and billionaires, while 60% backed government-provided healthcare for every American. The poll did not measure support for the entire progressive platform.

El-Sayed’s victory nevertheless unsettled parts of the Democratic establishment. Senate Democratic leader Chuck Schumer and Michigan Governor Gretchen Whitmer backed Stevens during the primary, but both moved to support El-Sayed once the result became clear.

“Whatever differences that we might have had in the primary, they pale in comparison to what unifies us,” El-Sayed said after his victory. He has since spoken with former president Barack Obama, whose representative confirmed the conversation.

Representative Alexandria Ocasio-Cortez described the progressive victories as part of a political “renewal” driven partly by younger voters.

“We’re grown adults with mortgages and kids,” she told ABC News. “And we — that generation is starting to be decisive at the polls.”

Ocasio-Cortez has not endorsed Francesca Hong, the Democratic Socialists of America-backed candidate for Wisconsin governor, who has moved away from earlier statements supporting the abolition of police and prisons.

Wisconsin voters were casting ballots on 11 August in a Democratic gubernatorial primary between Hong and Milwaukee County Executive David Crowley, the latest unresolved contest between the party’s progressive and establishment wings.