At first blush, it was hard to know what to make of a new poll in Iowa that diverged in an important way from one taken just a few weeks earlier.
The new CBS News/YouGov poll of Iowa had Joe Biden ahead with 29% but barely edging out Sen. Bernie Sanders, at 26%, with Sen. Elizabeth Warren at 17% and all other candidates in the single digits.
In a Monmouth poll of Iowa from early August, Biden (28%) and Warren (19%) were at a similar level, but Sanders was way back at just 9%.
Could this be attributed to some sort of Sanders surge in Iowa in August? Based on the news cycle of the past month, it’s difficult to see what would have made such a huge difference in his support. More likely, one of the polls is an outlier, or YouGov’s methodology, for whatever reason, is more favorable to Sanders.
But there’s one thing both polls agree on: When asked for their second choice, Warren leads both polls (at 19% in Monmouth and 29% in YouGov) with Biden well behind, making up the second choice of just 12% of Iowa Democrats in both.
Second choices are significant in Iowa, because the way the caucuses work, when lower-performing candidates do not make the viability threshold of 15%, they must direct their support elsewhere. Only three candidates — Biden, Warren, and Sanders — are polling above 15% in either of these polls. True, the viability thresholds apply to individual caucuses or areas, so there may be some places where certain candidates polling below 15% statewide can exceed the threshold. But such deviations are unlikely in lots of places, or else the candidates would be polling higher overall. So with such a large field of candidates, many of whom are in the low single digits, second choices are likely to prove decisive in Iowa.
That Warren seems to be so far ahead of Biden on this metric is good news for her, and worrisome news for his chances in the state.
