WASHINGTON      -     The House will hear from a singular witness Friday in the Trump impeachment hearings: Marie Yovanovitch, the former US ambassador to Ukraine who was targeted by the president’s allies in a “smear” campaign now central to the inquiry. The career diplomat, who served both Republican and Democratic presidents, is expected to relay her striking story of being suddenly recalled by Donald Trump and told to “watch my back” in a swiftly developing series of events that sounded alarms about the White House’s shadow foreign policy. She and other officials now testifying publicly in the historic House hearings scrambled to understand Trump’s actions, providing revelatory accounts that Democrats are now relying on to make the case that the president’s behavior is impeachable.

In particular, Yovanovitch and others have described Rudy Giuliani, Trump’s personal lawyer, as leading what one called an “irregular channel” outside the diplomatic mainstream of US-Ukraine relations. Asked during her closed-door deposition if anyone at the State Department who was alerted to Giuliani’s role tried to stop him, she testified, “I don’t think they felt they could.” With the start of a second day of historic hearings to consider removal of America’s 45th president, Democrats and Republicans are hardening their messages to voters as they try to saw public opinion.