WASHINGTON — President Donald Trump’s impeachment trial is shifting to questions from senators, a pivotal juncture as Republicans lack the votes to block witnesses and face a potential setback in their hope of ending the trial with a quick acquittal. Despite Trump’s defense team’s plea for it to “end now,” Senate Majority Leader Mitch McConnell privately told senators he doesn’t yet have the votes to brush back Democratic demands for witnesses now that revelations from John Bolton, the former national security adviser, have roiled the trial. Republican senators are trying to figure out a way to deal with fallout from Bolton’s forthcoming book, which provides a potential eyewitness account of Trump’s actions at the heart of the impeachment charges. But ideas being floated are fizzling almost as soon as they arise — among them, a witness “swap” with Democrats or issuing a subpoena for Bolton’s manuscript. RELATED: Cory Gardner noncommittal on subpoenaing John Bolton in impeachment trial One key Republican, Sen.