Official White House Photo by Tia Dufour(NEW YORK) — A year before the nation votes, top Democratic contenders have extended their leads over President Donald Trump in the 2020 presidential race, with broad public concerns about the president’s leadership in the latest ABC News/Washington Post poll. While former Vice President Joe Biden now leads Trump by 17 percentage points, other Democratic contenders show the most improvement: Vermont Sen. Bernie Sanders’ advantage vs. Trump has gone from a non-significant 6 points in July to 12 in September to 17 now. Massachusetts Sen. Elizabeth Warren’s has gone from 7 to 11 to 15 points.

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Impeachment is not the only factor, since the trend dates to early September. Among Trump’s broader challenges, six in 10 Americans or more say he’s not honest and trustworthy, lacks the kind of personality and temperament it takes to serve effectively and doesn’t understand their problems. Slightly smaller majorities doubt his deal-making, delivery of “needed change” to Washington and leadership generally.Further, as reported last week, half support Trump’s impeachment and removal from office, 54% say his policies have made the United States less respected globally, 58% disapprove of his overall job performance and 66% say he’s acted unpresidentially since taking office. He’s the first president in modern polling never to have achieved majority approval, with the lowest average approval rating on record.Yet Trump faced difficulties in 2016 and still prevailed in the Electoral College, if not in the popular vote. He remains strong in his base in this poll, produced for ABC by Langer Research Associates, with 70% support among conservatives vs. Biden, 76% among evangelical white Protestants and 79% among Republicans and Republican-leaning independents.The Democrats have risks of their own. Their support is heavily concentrated in a handful of groups — for example, young adults, those with more education, racial and ethnic minorities, people living in urban areas and those in the states Hillary Clinton won in 2016. Biden is +30 points vs. Trump in those blue states, for example, while just +7 points — not a statistically significant difference — in the 2016 red states.That said, 16% of leaned Republicans say they’d defect to Biden. Trump’s approval rating within his own party has dropped by 13 points since early July to a new low. And 30% of Republicans and Republican-leaning independents say they’d like to see the party nominate someone else as its 2020 presidential candidate. (In a different question in 1995, two in 10 Democrats preferred not to renominate Bill Clinton.)Trump’s presumed ace in the hole is the economy, and his fortunes may rest on its durability. As things stand, though, just a third of Americans, 34%, both say it’s improved since he took office and give him at great deal or good amount of credit for it.Copyright © 2019, ABC Audio. All rights reserved.