COLORADO SPRINGS, Colo. — Billionaire industrialist and conservative benefactor Charles Koch’s expansive political network will not help Donald Trump win the presidency. That’s the message from one of the Koch network’s chief lieutenants as hundreds of the nation’s most powerful Republican donors gather for a weekend retreat three months before Election Day. The exclusive gathering at the foot of the Rocky Mountains is open to donors who promise to give at least $100,000 each year to the various groups backed by the Koch brothers’ Freedom Partners — a network of education, policy and political entities that aim to promote a smaller, less intrusive government. At least three governors, four senators and four members of the House of Representatives are also scheduled to attend, including House Speaker Paul Ryan.