As Democrats calibrate their political messaging in advance of the November midterm elections, Senator Tammy Duckworth cautioned her party not to become too starry-eyed about the success in New York of Alexandria Ocasio-Cortez, who won an upset primary victory this week.

While Ocasio-Cortez’s candidacy might have been a fit for New York’s 14th congressional district, said Duckworth, the junior senator from Illinois, her brand of Democratic socialism would not work in the midwest. Ocasio-Cortez ran to the left of incumbent Joe Crowley, a 20-year veteran of Congress.

“I think that you can’t win the White House without the midwest,” Duckworth told CNN’s State of the Union. “And I don’t think that you can go too far to the left and still win the midwest.

“Coming from a Midwestern state, I think you need to be able to talk to the industrial midwest. You need to listen to the people there in order to win an election nationwide.”

Tammy Duckworth, the junior senator from Illionois, told CNN’s State of the Union: ‘You can’t win the White House without the midwest.’ Photograph: Alex Brandon/AP

Ocasio-Cortez is a former staffer to Bernie Sanders, a socialist from Vermont whose 2016 campaign for the Democratic presidential nomination was built on similar policies, foremost among them measures to close America’s wealth inequality gap, to those which Ocasio-Cortez, a bartender, campaigned on.

Sanders beat Hillary Clinton in multiple primary contests in the midwest, including Michigan, Indiana and Wisconsin. Donald Trump won all three states in the general election.

I don’t think that you can go too far to the left and still win the midwest

With control of Congress at stake in November, Democrats have tested various messages in recent weeks, from attacking Republicans on healthcare to abolishing the Immigration and Customs Enforcement agency, or Ice.

More broadly, the party faces the quandary of whether to try to expand its “big-tent” appeal to more minority and progressive voters, or to go after the working-class white voters who backed Barack Obama before voting for Trump.

Ocasio-Cortez, who ran on a platform of Medicare for all and free college tuition, on Sunday defended her identification as a “Democratic socialist”.

“I mean, it’s part of what I am,” she said on NBC New’s Meet the Press. “It’s not all of what I am. And I think that that’s a very important distinction. I’m an educator. I’m an organizer. And I believe that what we’re really seeing is just a movement for healthcare, housing and education in the United States.”

A major point of my campaign: in the safest blue seats in America, we should have leaders swinging for the most ambitious ideas possible for working-class Americans.



You’re largely not going to get gutsy risk-taking from swing-district seats.



So it’s not luck. It’s mindfulness. https://t.co/bOqgvTv0bM — Alexandria Ocasio-Cortez (@Ocasio2018) June 30, 2018

The Democratic establishment seems to have been caught wrong-footed by Ocasio-Cortez’s win, which dislodged a veteran legislator, Joe Crowley, who had been floated as a possible successor to the House minority leader, Nancy Pelosi.

First elected to Congress in 2012, Duckworth is a retired army helicopter pilot who lost both legs in the Iraq war. She won a decisive Senate election victory in 2016 against a Republican incumbent who had swooped on a seat vacated by Barack Obama in 2008.

Duckworth said Ocasio-Cortez’s appeal was probably limited to her district, which bridges the Bronx and Queens.

“I think it’s the future of the party in the Bronx, where she is,” Duckworth said. “I think that we, as legislators, need to listen to our constituency and get out there. I think what she did was, she did the hard work. She pounded the pavement, and she was out there talking to every one of her constituents. And I think that was the difference.

“She turned out her voters and reflected the needs of her district.”

Duckworth said the same of Joe Manchin of West Virginia, Heidi Heitkamp of North Dakota and Joe Donnelly of Indiana, Democratic senators in states that voted for Trump who are thought likely to support his forthcoming supreme court pick.

The three red-state Democrats “vote in whatever they need to do to take care of the people of their state”, Duckworth said. “They put their constituents first.”