Among Democrats in the United States, there is growing concern that Republicans will take power in the next presidential election.
Recently, Biden's opinion figures have fallen, while many Democrats have assumed that he will not stand for re-election given his advanced age.
The announcement also puts an end to any hopes that the current Vice President Kamala Harris could take over the presidency.
- The only thing I have heard is that he plans to line up again.
"I'm happy about that," Chris Dodd, a former senator, told the Washington Post.
The newspaper also writes that Biden is said to have told about the decision to a group at a charity fundraiser earlier in November.
"What he is saying in public is what he is convinced of," said former Pennsylvania Gov. Ed Rendell, who attended the fundraising event.
- He will not continue if he feels he can not do the job physically or emotionally, he continues.
Questioning the message
However, many Democrats question whether Biden really intends to stand for re-election.
- What will his health look like in the next few years?
You just have to look at the death statistics in the US to understand why I'm worried, says John Morgan, one of the biggest contributors to Biden's 2020 campaign.