House investigators have released the deposition by William Taylor, who runs the U.S. diplomatic mission in the Ukrainian capital of Kyiv.
Taylor, a career foreign policy specialist in the State Department, has been a central witness in the Ukraine affair. He described the intent by President Trump, as described by another diplomat, to put Ukraine's president "in a public box" committing to investigations that Trump thought might help him in the 2020 elections.
The expectation about those concessions was tied to engagement with Trump and continued assistance from the U.S. for Ukraine. Taylor told members of Congress that he objected to that policy and voiced his concerns with then-national security adviser John Bolton and in writing in a cable to Secretary of State Mike Pompeo.