help his own re-election but that he did it by employing a russian narrative that his own aides had tried and failed to debunk. >> everyone else told the president time after time, "this is nonsense." >> reporter: the spotlight today was on president trump's motives for pursuing two conspiracy theories-- one about the 2016 election, and one about joe biden. >> the one person who told president trump his theory is true? who was it? you know it was our adversary, russia. >> reporter: and, they argued, that with biden leading in the polls by last spring, mr. trump pressured ukraine to launch what he hoped would be an embarrassing investigation. >> no president has ever used his office to compel a foreign nation to help him cheat in our elections. >> on the basis of this russian propaganda, he withheld $400 million in military aid to a