How would a national primary campaign between Bernie Sanders and Hillary Clinton play out? Recently both David Wasserman and Nate Silver have attempted to sketch out what a longer-running electoral battle between Sanders and Clinton might look like.

Both Wasserman and Silver argue that because Sanders’s support stems from a base of white liberal Democrats, Bernie might be able to compete with Clinton in Iowa and New Hampshire, but he will struggle in states with different voter populations.

Let us leave aside the question of whether it’s reasonable to assume that Sanders — who has already defied conventional wisdom to push Clinton to the brink in the early states — cannot conceivably broaden his appeal to include non-white or non-liberal voters.

For now, I just want to consider the basic assumption about what Sanders’s base looks like right now: specifically, how “liberal” it really is. Both Wasserman and Silver assume, rather cavalierly, that a handful of national polls is sufficient to determine the character of the Sanders coalition. (Wasserman builds his entire model from a single NBC/Wall Street Journal survey.)

And in national polls, Sanders supporters do indeed tend to look the way that Wasserman and Silver describe: white, liberal, and often college-educated. But as I argued here a few days ago, the voter coalition that Sanders has built in Iowa and New Hamsphire — the states where he has campaigned intensively — looks somewhat different.

Sanders’s strength with voters making less than $50,000 a year — and his relative lack of appeal among voters making above $100,000 — sets him apart from Democratic primary challengers in years past like Bill Bradley, Howard Dean, and Barack Obama. All these “progressive” underdogs attracted their strongest support from wealthier voters, while struggling, in relative terms, to win lower-income support. (Nate Cohn notices the same trend in today’s New York Times.)

Compared to Dean or Obama, there’s also reason to believe Sanders’s early state backers are much less monolithically “liberal.” Public Policy Polling (PPP), which has tracked Iowa voter ideology most comprehensively, divides likely caucus-goers into five different groups, ranging from “very liberal” to “very conservative.” Their results, over three polls since December, do not at all conform to the Wasserman/Silver presumption that liberals are flocking to Sanders, while moderates support Clinton.

Very Liberal (23%–25%)

IOWA (PPP) Sanders Clinton PPP Jan 27–28 45.0% 47.0% PPP Jan 8–10 47.0% 48.0% PPP Dec 10-13 35.0% 59.0% Average 42.3% 51.3%

Somewhat Liberal Liberal (31%–37%)

IOWA (PPP) Sanders Clinton PPP Jan 27–28 36.0% 53.0% PPP Jan 8–10 37.0% 51.0% PPP Dec 10-13 38.0% 54.0% Average 37.0% 52.7%

Moderate (32%–36%)

IOWA (PPP) Sanders Clinton PPP Jan 27–28 45.0% 41.0% PPP Jan 8–10 38.0% 44.0% PPP Dec 10-13 30.0% 52.0% Average 37.7% 45.7%

Conservative (6%–7%)

IOWA (PPP) Sanders Clinton PPP Jan 27–28 42.0% 43.0% PPP Jan 8–10 37.0% 44.0% PPP Dec 10-13 45.0% 28.0% Average 41.3% 38.3%

Very Conservative (1%–3%)

IOWA (PPP) Sanders Clinton PPP Jan 27–28 21.0% 36.0% PPP Jan 8–10 15.0% 44.0% PPP Dec 10-13 9.0% 23.0% Average 15.0% 34.3%

Overall

IOWA (PPP) Sanders Clinton PPP Jan 27–28 40.0% 48.0% PPP Jan 8–10 40.0% 46.0% PPP Dec 10-13 34.0% 52.0% Average 38.0% 48.7%