In this image from video, House impeachment manager Rep, Adam Schiff, D-Calif., holds redacted documents as he speaks during the impeachment trial against President Donald Trump in the Senate at the U.S. Capitol in Washington, Wednesday, Jan. 22, 2020. [Senate Television via AP]

The team led by Rep. Adam Schiff, the chairman of House Intelligence Committee, constructed a gripping account of Trump's political pressure on Ukraine and attempt to cover up the "corrupt scheme" central to the charges. But the limits are apparent. Prosecutors must rely on the same loops of videotaped testimony -- ambassadors, national security officials and even the president himself -- after Trump's GOP Senate allies blocked new witnesses.