Senate Majority Leader Mitch McConnell said told Republican senators late Tuesday that there are currently not enough GOP votes to block witnesses from being called in President Donald Trump's impeachment trial, the Wall Street Journal reported. McConnell reportedly made the comment in a private meeting with Republican senators. A move to call witnesses would need 51 votes to pass, and with a 53-seat majority, Republicans can only afford three senators to defect. There has been a new push to hear testimony from former national security adviser John Bolton in recent days, following a New York Times report Sunday that said his upcoming book details how Trump told him security aid to Ukraine should be blocked until Ukrainian officials agreed to investigate Democrats, including the Bidens -- potentially undermining a key part of Trump's defense.