Take the new Post-ABC poll released Sunday. Overall, the numbers remain solid for Biden. Though Warren is at 23 percent, reflecting her rising support over the past few months, and Sanders continues to poll at just under 20 percent in the Democratic electorate, Biden still has the support of 28 percent of Democrats, just two points fewer than in July. More-moderate threats to Biden have either receded, as in the case of Sen. Kamala D. Harris (D-Calif.), or are still stuck in single digits, like South Bend, Ind., Mayor Pete Buttigieg.
For his consistent polling strength, Biden should thank older voters. Among adults under 49, just 17 percent back Biden, compared with 22 percent for Warren and 28 percent for Sanders. Conversely, 37 percent of those 50 and older back Biden, with 20 percent for Warren and 10 percent for Sanders. The difference between old and young Democrats is bigger than the differences between male and female Democrats, white and nonwhite, moderate and liberal, or any other demographic breakdown.
If the Democratic primary were a national contest, Biden’s lead is strong enough — nearly 9 percent in polling averages — that this age gap would be mostly a curiosity. But unfortunately for Biden, his standing is far shakier in Iowa and New Hampshire, and since 1992 no Democrat has won the nomination without winning at least one of those two states. Why is Biden struggling there? Because the age gap is even wider. In a CNN/University of New Hampshire poll of New Hampshire Democrats, Biden sits at 15 percent, trailing Sanders at 21 percent and Warren at 18 percent. The former vice president is supported by 22 percent of Democratic voters 50 and older, compared with just 8 percent of those under 50. And in the New York Times-Siena College Research Institute poll of Iowa, the explanation for Biden’s fourth-place showing at 17 percent starts and ends with the fact that, among likely caucus-goers under 45, he receives less than 3 percent support.
Four years ago, in primary after primary, older voters were Hillary Clinton’s most consistent supporters against Sanders. Just like 2016, then, it will come down to turnout: The fact that voters over 45 made up three-fifths of all Democratic primary voters in 2016 gave Clinton an insurmountable advantage. If older voters maintain that margin this time around, that would greatly ease Biden’s path to reclaiming the top spot in Iowa and/or New Hampshire. If young voters show up in greater numbers, then Warren’s or (especially) Sanders’s path becomes notably easier. Given the narrow margins, even if the average age of the electorate shifts only a little, that may make all the difference.