True, the vice president does have an advantage the next time the party needs a new nominee, which in Biden’s case could be four years from now. But in the meantime, the vice president has no real power and little chance to accomplish anything independent of the president.
Basically, no one takes the vice president seriously after election day. Just ask Mike Pence.
Plus, if Biden wins, the Democrats will be moving into the White House in the middle of a pandemic and economic recession. The next few years promise to be a very bumpy ride. Barack Obama and the Democrats saved the nation from economic collapse when he took office, and their reward was a blowout loss in the 2010 midterm elections.
On the other hand, the attorney general has legitimate power. From atop the Justice Department, the boss can make a real mark on everything from police reform to racial justice to prosecuting corporate misdeeds.