In an interview with ABC' "This Week" Sunday, Sen. Bernie Sanders pushed back on the idea that he and Sen. Elizabeth Warren are interchangeable candidates within the 2020 Democratic field, arguing that Warren is a "capitalist through her bones" and he is a democratic socialist.
Why it matters: Sanders and Warren appeal to a similar progressive base of the Democratic Party. But while Sanders' support seems to have largely hit a plateau, Warren has continued to rise in the polls, overtaking the more moderate Joe Biden in the national RealClearPolitics average of polls last week for the first time this cycle.
Between the lines: In a recent CBS News poll of Democrats in early voting states, 43% said that the 78-year-old Sanders — who recently had a heart attack — is "too old to serve effectively as president." 28% said the same of the 76-year-old Biden, while only 4% said so for the 70-year-old Warren.
Go deeper: Sanders says he felt symptoms for weeks, will release medical records