For Biden and Harris, a Delicate and Sometimes Awkward Dance

In the days after President Biden’s disastrous debate performance, aides to Vice President Kamala Harris got word of an exchange that a staff member from the White House legislative affairs office had with a member of Congress about why Democrats should continue to support Mr. Biden’s re-election bid.

Ms. Harris’s aides were concerned that in making the case for Mr. Biden, the legislative affairs office had denigrated her political strength and suggested that she would not be as strong a candidate against Donald J. Trump.

The aides quickly reached out to Jeff Zients, the White House chief of staff, to alert him about the call.

Their message was that it was fine for the administration’s surrogates to whip support for Mr. Biden — and that they were totally behind that effort — but that Mr. Biden’s team needed to be careful not to do it at the expense of degrading the vice president.

Mr. Zients got in touch with the White House director of legislative affairs, Shuwanza Goff, and told her that her staff needed to be disciplined about not undercutting the vice president as the president’s team navigated the treacherous topic of Mr. Biden’s chances of winning and what the uncertainty meant for Ms. Harris.