Silvanus said:
How does that square with Biden failing badly in states where Bloomberg didn't run?
It seems likelier to me that Biden's strength came from a largely unchallenged perception that he was a safe pair of hands-- moderate-to-centre, electable, experienced... and that the exposure of the Primary campaign exposed that perception to be off-target and unrealistic.
We certainly could take the notion that Biden's support drifted away to other candidates roughly proportionally, and that Bloomberg then took away from the other candidates also proportionally, so that Biden experienced a net loss, Bloomberg a similar net gain, and everyone else was mostly evens. I'd bet some of that sort of vote shifting happened to at least some extent, but ultimately I'd suggest Biden just lost a huge chunk of votes direct to Bloomberg.
Biden's collapse (at a national level) really appears at the start of February, losing half his support in about two weeks. However, this is not necessarily mirrored by state results. Given preceding polls, according to national trends we'd have expected Biden's results to be about 10%, 7-8% and 12% respectively for Iowa, New Hampshire and Nevada. His actual results were ~16%, 8% and 20% (with Buttigieg seeming to have been the largest beneficiary). Thus I would suggest Biden's disappointing state results so far are
better than nationwide polls would indicate he should have done, and I would further suggest that Bloomberg not being on the ballot is a significant factor why.
I'm not sure anything about perception of Biden has changed much. He's mostly... "dull", occasionally a doofus, and his rude explosion at some audience member recently is nothing he hasn't done several times before. I'm not sure there's anything obvious that happened in February to change perceptions of him: no major screw up or embarrassment. The worst might be that something about his son in Ukraine could come back to bite, but that was hardly new in Feb 2020.
I don't think anything about the primary campaign has made Biden seem worse. He's been solid and uninspiring in debates, not made any more gaffes than normal, etc. Normally, when well ahead, being boringly safe is often a winning tactic, like football teams playing for time when they're 2-0 up. I don't think there is anything to explain his collapse except an entrant to the race who steps on his territory: Sanders and Warren have always been appealing to a different bloc within the party, and all the other guys are (relatively) little league nobodies and chancers. But Bloomberg is a big name with a major political record who would carry an aura of competence from his billions and his time as NY mayor, and offers something to Democrats who want a safe, major brand to head the ship later in the year.
