Well-off white people with a college degree living in the suburbs really like the Pete.
He's got the more moderate of that group while Warren has the more liberal of them, but they both share very similar demographic support. It's why there are so many Warren and Buttigieg supporters with the other as their second choice. Even on here, I can name three people right away that have them as their top 2.
I'd name Warren and Buttigieg as my top two candidates right now too, although this has also a lot to do with me thinking that Biden and Sanders are way too old and also past their political prime. Biden in particular isn't really the representation of change and a new beginning, with his 45 years in federal politics and three presidential runs. Sanders could get another heart attack at any time and he's the losing candidate if the last primaries. Any other candidate besides these four is a non-factor.
