Here's why it would be tough for Democrats to replace Joe Biden on the presidential ticket

President Joe Biden’s halting debate performance has led some in his own party to begin questioning whether he should be replaced on the ballot. There is no evidence Biden, who debated former President Donald Trump on Thursday night, is willing to end his campaign. And it would be nearly impossible for Democrats to replace him unless he chooses to step aside. Every state has already held its presidential primary. Democratic rules mandate that the delegates Biden won remain bound to support him unless he tells them he’s leaving the race.