What is Super Tuesday and how does tomorrow's voting work?

Super Tuesday, on March 5, is when the largest number of states will be holding presidential primaries or caucuses. Over a third of all the available delegates for both the Republican and Democratic nominations are at stake on Super Tuesday.

President Biden is the leading contender for the Democratic nomination, and he has no substantial primary challenge, while former President Donald Trump is leading former South Carolina Gov. Nikki Haley in the Republican nomination race.