Hunter Biden is standing trial this week on federal charges of illegally possessing a firearm after allegedly lying about his status as a drug user when buying a pistol in 2018. President Joe Biden's son has previously pleaded not guilty to the charges, saying that he entered a rehab program before purchasing the firearm and checked off "no" on a federal form that asked whether he was an "unlawful user of or addicted to any controlled substance." The trial, which began on Monday,...