By some measures, this week was the stock market's worst since the 2008 financial crisis as traders worried about the market impacts of the new coronavirus. The administration continues its effort to project stability and preparedness. If the downturn lasts though, it does not bode well for the president's reelection chances.Also, former Vice President Joe Biden faces what may be the most pivotal day of his half-century long political career in Saturday's South Carolina primary. Ahead of the vote, our portrait of his candidacy at this inflection point.This episode: congressional correspondent Kelsey Snell, campaign correspondent Asma Khalid, senior political editor and correspondent Domenico Montanaro, and chief economics correspondent Scott Horsley.