For Bernie Sanders and Marco Rubio, the Iowa Caucus Is Do or Die

After what already feels like a very long campaign, the candidates will face their first real test Monday as Democrats and Republicans will caucus in Iowa. The Iowa caucus will not produce a nominee-on the Democratic side it won’t even winnow the field, because if Martin O’Malley has stuck with his lifeless campaign thus far, there is no reason for him to drop out when he gets no delegates in Iowa, but it will nonetheless be significant. Once results from Iowa are in, the rest of the race, or at least the next few weeks, will begin to assume a clearer shape.