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Boston’s North Shore seems as if it should be prime Elizabeth Warren territory. It is home to working-class towns, and it’s a short drive from Warren’s own house.

But ever since she entered electoral politics in 2012, she has struggled on the North Shore. When she defeated Scott Brown, the Republican incumbent senator, that year, she lost in places like Haverhill, Peabody, Saugus and Methuen. Last year, when Warren won re-election easily, she performed worse in those towns than Maura Healey, the Democratic attorney general, who was also on the ballot.

As Warren has risen to the top of the presidential primary field, her North Shore struggles underscore the biggest question about her campaign: If she were the nominee, could she win back working-class voters who swung to Donald Trump in 2016?

There are real reasons for concern. In her 2012 and 2018 Senate races, Warren struggled in other blue-collar parts of Massachusetts, like the areas around Springfield and Worcester. And in most state polls asking voters to choose between Trump and potential Democratic nominees, Warren looks considerably weaker than Joe Biden.