What was the worst day for the Biden campaign?

[Shaula🏳️‍⚧️]

What gaffe or moment cost Biden the most voters during the election cycle (post-Bernie dropping out)

[Fmr. Gov. NickG]

The day he chose Harris as a running mate.

[forza nocta]

The day he chose Harris as a running mate.

Wasn’t that the day he shattered his fundraising record

[Crumpets]

If we can include the primaries, then obviously all the first three were terrible days for him. In the general, knowing what we know now, probably either the Kenosha riots specifically (but not the broader protest movement) or the death of RBG.

[Alben Barkley]

Yeah it's definitely the early days in the primaries if that counts.

if not... Maybe when the Hunter stuff was leaked just because of how disgraceful that was and mortifying it must have been to his family, not because it actually hurt him.

[brucejoel99]

If primary days count, then definitely whichever early September 2019 day it was on that the Biden campaign only managed to raise like $24K in a single day.

[SnowLabrador]

Probably the day RBG died. That's what juiced up Republican turnout.

[RussFeingoldWasRobbed]

1. Kenosha Riots
2. RGB
3. Chaz

[Beet]

Probably either the Iowa caucus or New Hampshire primary.

[Kalimantan]

Probably the night of election day when for a while it looked like he might lose. That can't have been fun.

[I need an explanation]

Probably either the Iowa caucus or New Hampshire primary.

New Hampshire was worse. At least with Iowa the delayed results and super closeness between Buttigieg and Sanders overshadowed his horrible showing.

[Paul Biya isn’t going far enough]

Election night.

[Progressive Pessimist]

In hindsight it was either the time when the Tara Reade story was bubbling under the surface or "you ain't black!" Those may have been the only times when Biden attracted some real negative attention, as fleeting as they were. Otherwise he managed to avoid negative coverage pretty well for this entire election, and it probably mattered.

I wasn't considering the primary though, the stretch between Iowa and South Carolina were definitely rough for the campaign.

[Fmr. Gov. NickG]

The day he chose Harris as a running mate.

Wasn’t that the day he shattered his fundraising record

He would have shattered it by more if he had chosen Warren.

[Fmr. Gov. NickG]

Probably either the Iowa caucus or New Hampshire primary.

It was definitely New Hampshire, except the OP specified after Bernie dropped out.

[HagridOfTheDeep]

In hindsight it was either the time when the Tara Reade story was bubbling under the surface or "you ain't black!" Those may have been the only times when Biden attracted some real negative attention, as fleeting as they were. Otherwise he managed to avoid negative coverage pretty well for this entire election, and it probably mattered.

I wasn't considering the primary though, the stretch between Iowa and South Carolina were definitely rough for the campaign.

Honestly, to me, the "you ain't black" thing actually seemed to be a watershed, "wake-up-call" moment for the Biden campaign where they actually made a real effort to reach out to black voters. Who knows how the Rust Belt would have turned out for Biden if he didn't actually make a play for this community's votes?

[EastOfEden]

The three great underperformances.

February 3
February 11
November 3

[Don't blame me I voted for Harris]

Iowa caucus.

[Mr. Morden]

Probably the day Hunter Biden joined the board of Burisma.  Granted, that was years before the campaign officially started, but it was still the worst day for the campaign.

Maybe the second worst day came decades before that, the day that Biden confronted Corn Pop....an incident which may have cost Biden a couple of percentage points worth of the black vote.

[Mr. Third-Wayist]

September 8, 1941, The day Bernie was born (cost him some of the progressive vote)