The nomination season for presidential candidates begins with the Iowa caucuses. That makes it important for a candidate to do well in that state, and a win in Iowa could propel a candidate to wins in other states.
Last May, the big dogs in Iowa were Joe Biden and Bernie Sanders (both at 24%) and Pete Buttigieg at 14%. The campaign of Elizabeth Warren was off to a slow start, coming in fourth with 12%. Kamala Harris was in fifth with 10%. But a lot has changed since May.
In the August poll of Iowa Democrats, Warren now has a significant lead (28%) -- putting her 11 points ahead of Biden and Sanders (both at 17%), 15 points ahead of Buttigieg (13%), and 20 points ahead of Harris (8%).
Warren is the only one of the major candidates that has increased her support in Iowa since May -- going from 12% to 28%. All of the others have seen their support shrink.
These numbers are from the new Change Research Poll -- done between August 9th and 11th of a sample of 621 voters likely to participate in the Iowa caucuses. The margin of error is 3.9 points.