What to know about Day 3 of the Republican National ConventionSen. JD Vance focused heavily on his family and his upbringing in Appalachia in his first speech since being named former President Donald Trump's running mate. Trump and Vance have each attended parts of the RNC, but this is the first time one of them has spoken onstage.The RNC theme today was "Make America Strong Once Again," with a focus on military and foreign policy. Several of the speakers tonight leaned heavily on anti-migrant sentiments or inflammatory rhetoric. Former Trump White House official Peter Navarro was given a standing ovation and resounding applause when he took the stage hours after being released from prison. Navarro served a four-month sentence for defying a subpoena from the House Jan. 6 committee.President Joe Biden tested positive for Covid-19 today and is experiencing mild symptoms, the White House said. Biden cut his trip to Las Vegas short and flew back to Delaware, where he's expected to self-isolate. He told reporters in Nevada, "I feel good."