Whom did they poll? People at the DNC HQ?
Yes and at MSNBC,CNNN,and people in the DC burbs.
Morning Consult and Politico it was an online poll of 1960 registered voters.
Here are the results:
https://morningconsult.com/wp-content/uploads/2019/08/190816_crosstabs_POLITICO_RVs_v2_JB.pdf