As the third day of the ongoing impeachment trial of President Trump wrapped up in the Senate chamber, most of the drama was elsewhere -- with one witness for the Democrats accusing a Republican senator of "defamation" and "slander," and Republicans vowing to aggressively highlight alleged corruption by Hunter Biden. The off-field spat began Thursday evening on Twitter, when Tennessee GOP Sen. Marsha Blackburn quoted the commanding officer of Lt. Col. Alexander Vindman as saying that Vindman was a "political activist in uniform." [cut] Vindman's legal team fired back within hours.