STORY: Vice President Kamala Harris is the top alternative to potentially replace U.S. President Joe Biden if he decides not to continue his reelection campaign.

That's according to seven senior sources at the Biden campaign, the White House and the Democratic National Committee with knowledge of current discussions on the topic.

Talk of replacing Biden at the top of the Democratic Party's presidential ticket mounted after his fumbling, sometimes-incoherent, and widely-panned first-debate performance against Republican rival Donald Trump last week.

Some have floated alternatives - like Democratic governors Gavin Newsom from California, Gretchen Whitmer of Michigan and Josh Shapiro of Pennsylvania.

But sources, who did not wish to be named, told Reuters that side-stepping Vice President Harris is wishful thinking, and almost impossible.

These sources said 59-year-old Kamala Harris would take over money raised by the Biden campaign and inherit campaign infrastructure.

Sources also said she also has the highest name recognition among all the alternatives, and the highest polling among Democrats who could seriously be considered a candidate.

In a Reuters/Ipsos poll published Tuesday, Harris trailed Trump by just one percentage point at 42% to 43%, a difference that was well within the poll's 3.5 percentage point margin of error.

That makes her statistically just as strong as Biden, who pulled even with Trump in the latest survey.

"What I can say is that just to take a step back, it was a bad night"

White House Press Secretary Karine Jean-Pierre acknowledged on Tuesday the president's poor performance at the debate. But she said he will continue to make his case for a second term.

"And when you look at the record of President Biden versus former President Trump, you see President Biden, who has delivered the strongest recovery in modern history versus the previous administration, whose plans hurts the middle class. And President Biden, who is committed to protecting our fundamental freedoms versus the former president, the previous administration doing everything that they could and they did to overturn Roe v Wade. And they are responsible for that."

The decision to step aside would be Biden's, and his alone.

And Harris's aides dismissed any talk of a Democratic ticket that doesn't include both Biden and Harris.

In a statement, her office said, "Vice President Harris looks forward to serving a second term with President Joe Biden."