Debate takeaways: Biden slips, Harris soars, Dems tilt left

The first TV debates of the 2020 White House primaries have underlined Joe Biden's vulnerability to a younger generation in a Democratic Party that is leaning increasingly to the left.The two-night event -- sometimes tense, often compelling -- that concluded Thursday in Miami introduced American voters to the top 20 Democrats aiming to challenge Republican incumbent Donald Trump next year.The most experienced, best-known candidate in the campaign came under repeated assault Thursday, notably fro