6 big questions ahead of final debate before start of voting

Democratic presidential candidate former Vice President Joe Biden speaks alongside Iowa attorney general Tom Miller during a stop at a campaign field office, Monday, Jan. 13, 2020, in Des Moines, Iowa. (AP Photo/Patrick Semansky)

Tuesday marks the last time the leading Democratic presidential contenders will face a national audience on the debate stage before primary voting begins, making it the most significant moment of the 2020 primary season to date. The prime-time faceoff comes just 20 days before Iowa’s caucuses as polls suggest the nomination is truly up for grabs. Heading in, there are new signs of tension among all the top-tier candidates, particularly Bernie Sanders and Elizabeth Warren. If ever there has been a time for the six contenders on stage to take the gloves off, this is it.