For the past generation, Democratic presidential candidates have mostly talked of redistributing the rewards of American capitalism while leaving its basic structure intact.

Elizabeth Warren promises to break that mold. The Massachusetts senator, who has moved to the front ranks of the field, talks of remaking capitalism from the ground up. As president, she would drastically cut back the size and influence of big business, push private companies from parts of the economy altogether, and shift power to government and to labor.

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