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

U.S. 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 before November.

U.S. 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 before November.

There is no evidence Biden is willing to end his campaign. And it would be nearly impossible for Democrats to replace him unless he chooses to step aside.

Here's why:

Every state has already held its presidential primary. Democratic rules mandate that the delegates Biden won remain obligated to support him at the party's upcoming national convention unless he tells them he’s leaving the race.

Biden indicated that he had no plans to do that, telling supporters in Atlanta shortly after he left the debate stage, “Let's keep going.” Biden campaign spokesperson Lauren Hitt was even clearer, saying Friday: “Of course he's not dropping out.”

The conventions and their rules are controlled by the political parties. The Democratic National Committee could convene before the convention opens on Aug. 19 and change how things will work, but that isn't likely as long as Biden wants to continue seeking reelection.

The current rules read: “Delegates elected to the national convention pledged to a presidential candidate shall in all good conscience reflect the sentiments of those who elected them.”