He, Pompeo and Defense Secretary Mark T. Esper had collectively pressed the president about releasing the aid nearly a dozen times in the preceding weeks after lower-level officials who worked on Ukraine issues began complaining about the holdup, Bolton wrote. Trump had effectively rebuffed them, airing his long-standing grievances about Ukraine, which mixed legitimate efforts by some Ukrainians to back his Democratic 2016 opponent, Hillary Clinton, with unsupported accusations and outright conspiracy theories about the country, a key American ally.