This combination of 2013 and 2012 file photos shows brothers David, left, and Charles Koch. In July 2018, an estimated 500 Koch donors _ each having committed at least $100,000 annually _ gathered in the mountains of Colorado for an invitation-only “seminar” that featured a handful of elected officials and high-profile influencers. The conservative network remains one of the nation’s most influential political forces. (Phelan M. Ebenhack, Bo Rader/The Wichita Eagle via AP)