Calling Hillary Clinton’s selection of Sen. Tim Kaine (D-VA) as her running mate an “assault on the progressive base of the Democratic Party,” Norman Solomon, the head of the Bernie Delegates Network, said on Monday in Philadelphia that his group of 1,200 delegates is having “very serious discussions” about challenging Kaine’s nomination on the floor. Solomon said they do not have a candidate in mind and acknowledged their challenge would fail but nonetheless said the discussions would continue. He said there was enthusiasm among Sanders’s delegates for Sens. Elizabeth Warren (D-MA) and Sherrod Brown (D-OH) and Labor Secretary Tom Perez. He said the delegates would need a potential vice presidential nominee to formally sign off before that person’s name is put into nomination. Outside the convention halls, Sanders demonstrators were reportedly chanting “Never Hillary” as they marched. Sanders’s allies who already distrusted Clinton and Democrats became even more enraged this weekend when a trove of emails released by Wikileaks confirmed all of their suspicions about how the Democratic National Committee had a thumb on the scale for Clinton throughout the primary to “rig” the election for her. "Feel the Bern" chant hypes up the crowd, followed by smaller "Never Hillary"