Top Donald Trump donors tried to set up a meeting between the GOP presidential nominee and Charles Koch in Colorado Springs on Friday, but Koch aides rejected the entreaties, according to two Republicans with knowledge of the outreach. Koch and his brother David Koch, who helm an influential network of advocacy groups and major conservative donors, have been sharply critical of Trump’s rhetoric and policy stances and have indicated they do not intend to support his campaign. Trump in turn has blasted the Kochs and other major conservative donors as puppeteers to whom his GOP primary rivals were beholden, while...