I mean, she sorta has to, though, right? Biden is consolidating a plausible coalition of old, white (doing pretty well with black Dems too), moderate Dems. She and Bernie are battling for more liberal and younger voters. If she doesn’t start taking some of Bernie’s voters, Biden’s path looks easier and easier.
There is more than one kind of attack, and certainly many may not be received well, but Biden would certainly enjoy voting percentages of 30/17/15 for him, Warren, and Bernie all the way to the convention. Consolidation of those more liberal voters sooner rather than later is important.
The way I think about it it’s like picking marbles out of a bag for day one: there are C(15,10) ways to pick only white people for day 1 and there are C(20,10) total possible arrangements, and the marbles left in the bag are day 2. But it’s different from the usual marble problem because there are exactly twice as many situations where only white people are left in the bag and we have to account for those.
Looking at these headshots they’re putting at the bottom of the screen while the TV’s on mute, and almost none of them look presidential in their headshots. The two closest are Bullock and Bennet. Everyone else other than Glamour Gabbard is not working that camera well. Not sure why CNN would do it like that. Just give them their standard airbrushed look from a photo they choose.