The Note: Biden's past lingers over Democrats' future

The TAKE with Rick Klein

The candidate with the longest past wants to look to the future. His rivals want to keep looking at his past.

Caught in that rhetorical crossfire are the arguments likely to define the Democratic primary race over the half-year until voting starts.

Former Vice President Joe Biden was stronger Wednesday night than he was at the first debate a month ago. He had Sen. Kamala Harris to share some heat with, in a race that remains wide open in terms of candidates and issues.

Moving forward in the race, there will be fewer candidates to attack Biden, but there will also be fewer targets to deflect the attention.

However, the focus on Biden's long record -- on race, women's rights, climate change, immigration and even, if not especially, health care -- isn't about to fade.

Biden's easiest shield -- invoking his association with former President Barack Obama -- doesn't offer everything he hoped it would. Several candidates, including Sen. Cory Booker and Mayor Bill de Blasio, called him out on it.

Candidates love to say they have visions that take the country forward. But so many Democratic Party obsessions are caught up in a certain candidate's very long past.

The RUNDOWN with Benjamin Siegel

He's one of the few presidential candidates who doesn't serve in Congress, but former Housing and Urban Development Secretary Julian Castro offered a new argument for the House to impeach Trump in Wednesday night's debate.

House Democratic leaders and moderate members worry that impeaching Trump would only lead to his acquittal by the GOP-held Senate -- something the president could tout as vindication heading into the 2020 election and use to his advantage. In Castro's telling, Trump could do the same if Democrats decide not to take it up in the House.

"If they don't impeach him, is he going to say, 'You see, you see, the Democrats didn't go after me on impeachment. And you know why? Because I didn't do anything wrong,'" said Castro, whose twin brother, Joaquin, serves in the House and has called for impeachment. "Conversely, if Mitch McConnell is the one that lets him off hook, we're going to be able to say, 'Well sure they impeached him in the House, but his friend, Mitch McConnell, 'Moscow Mitch,' let him off the hook.'"

It's impossible to predict how Trump would handle the politics of impeachment heading into the election. But as nearly half of all House Democrats are calling for formal impeachment proceedings, it's not hard to imagine some of the more fervent impeachment advocates making the same case as Castro -- who was the first presidential candidate to call for proceedings.

The TIP with Rachel Scott and MaryAlice Parks

As Trump prepares to address his supporters at a rally in the battleground state of Ohio on Thursday, the controversy from his last rally lingers. It's been two weeks since his supporters erupted in "send her back" chants during a rally in North Carolina after he attacked four minority Democratic congresswoman.

Will his supporters turn to racists chants again? And if chants like that do break out again, how will the president respond?

A clue as to how Democrats might pivot if Ohio's rally becomes a redux could perhaps be found in Democratic National Committee chairman Tom Perez's preamble ahead of Wednesday night's debate in which he accused the president of trying to "distract" and "divide" around racial lines.

It might also be found in the closing arguments of the candidates who feel, as summed up by Sen. Kirsten Gillibrand: "Donald Trump has really torn apart the moral fabric of the country. Dividing us on every racial line, every religious line, every economic line he can find."

THE PLAYLIST

ABC News' "Start Here" podcast. Thursday morning's episode features ABC News Senior Congressional Correspondent Mary Bruce in Detroit, who breaks down the latest Democratic debate. ABC News' James Longman tells us more about the reported death of Osama bin Laden's son. Then ABC News Chief Business and Economics Correspondent Rebecca Jarvis decodes the moves made by the Federal Reserve on Wednesday. http://apple.co/2HPocUL

ABC News' "Powerhouse Politics" podcast. Former Virginia Gov. Terry McAuliffe, author of the new book "Beyond Charlottesville: Taking a Stand Against White Nationalism," expressed concern over the topics discussed during the presidential primary debates as well as the stances of some candidates. He spoke with ABC News Political Director Rick Klein and Deputy Political Director MaryAlice Parks. https://bit.ly/2FA0CIm

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