New York: At the most recent presidential primary debate, Elizabeth Warren was attacked from all sides. It confirmed a growing view that momentum was on her side and the proud progressive from Massachusetts was becoming the candidate to beat.

A month later, as Democrats prepare for their next debate on Wednesday (Thursday AEDT), Warren is flat-lining. Meanwhile, a new contender has caught fire in the crucial early primary states.

The four candidates are expected to debate one another today. Credit:AAP

Pete Buttigieg, the 37-year-old mayor from Indiana, has shot to the lead in Iowa – a stunning turnaround from the start of the year when he was almost completely unknown on the national political stage.

Iowa wields outsized influence in American politics because it is the first state where Democrats and Republicans hold their presidential primaries. A strong performance there can put a candidate on the path to victory or sink their presidential hopes.