WATCH: All the key moments from Day 1 of the Trump impeachment hearings in less than 15 minutes
“In an instant I realized that one of the key pillars of our strong support for Ukraine was threatened," Bill Taylor, the top U.S. diplomat in Ukraine, told lawmakers in the first public hearing in the House impeachment inquiry of President Donald Trump. Taylor and George Kent, deputy assistant secretary of state for European and Eurasian affairs, shared how they became concerned about the U.S. withholding aid to Ukraine in an attempt to get that nation to investigate one of President Donald Trump’s political rivals. The diplomats outlined how an unofficial channel for U.S. policy toward Ukraine was led by President Donald Trump’s personal lawyer Rudy Giuliani. "The irregular policy channel was running contrary to the goals of longstanding U.S. policy,” Taylor testified. Here are highlights from their testimony.