The Washington Post via Getty Images Trump supporters rally outside the US Capitol on Jan. 6, 2021. WASHINGTON — The leader of a local chapter of the Proud Boys extremist group pleaded guilty Friday to conspiring to obstruct Congress and assaulting police at the US Capitol on Jan. 6, taking a deal that includes an agreement to cooperate with the investigation going forward. Charles Donohoe’s cooperation gives prosecutors inside access to a Proud Boys leadership circle that included the group's former national chair Enrique Tarrio. As part of his plea, Donohoe not only admitted to his own role in planning...