In doing so, and even with Biden’s numbers dropping of late, Democrats are leaning into an approach that past administrations have shunned: freely tying their own fortunes to the outcome of an early, down-ballot race. A win for Youngkin, Biden’s aides and allies say, may not scuttle his domestic agenda. But it would be the first domino to fall, foreshadowing potential problems with the party’s planned midterm quest to paint Republicans as too extreme to govern.

“If they want to make sure that Donald Trump is front and center running for president again, then don’t show up to vote,” warned Chris Korge, national finance chair at the Democratic National Committee, who is close with McAuliffe. “This could be the ballgame here.”…

Biden’s all-in act is a break from his former boss, Barack Obama, whose team worked to distance itself from the Democratic gubernatorial campaign in 2009 and, in 2013, talked up the challenges of winning in Virginia given their control of the White House. Biden’s approach comes with obvious risks, offering Republicans an added measure to gloat about White House backlash should Youngkin prevail. Nevertheless, the president’s team and other party leaders have come to the conclusion that there is no other path.

For one, there are too many parallels between Biden and McAuliffe. Both are establishment figures whose tempered views align on virtually every major issue. They’ve also concluded that to adequately stoke turnout, Democrats need to emphasize the existential stakes of the race, something Obama himself drove home in his speech for McAuliffe this weekend and Biden offered on the campaign trail over the summer.