The divide in the Democratic Party is often described as a progressive wing pitching big ideas that are controversial in swing districts and purple states vs. a centrist wing that pushes a more modest — and less electorally risky — agenda. But right now, more moderate Democrats such as Sens. Joe Manchin III (W.Va.) and Kyrsten Sinema (Ariz.) and Rep. Kathleen Rice (N.Y.) are balking at a reconciliation bill that is full of ideas that poll well, such as universal free preschool and reducing prescription drug costs, and is being pushed by President Biden, a fellow moderate Democrat.

What gives? Well, the Democratic Party’s divide isn’t being described accurately — or at least completely. Some of the moderates aren’t just wary of controversial ideas. They are wary of the party doing too much, even if it polls well.

It’s important to understand that most moderate and purple-state Democrats are fully on board with the reconciliation bill. The resistance is coming from about 10 or so House Democrats and Manchin and Sinema in the Senate. For these members, I think four factors are at play.

First, some of them are fairly conservative, electoral considerations aside. So they don’t strongly oppose government spending or abortion rights, like conservative Republicans, but they are temperamentally conservative, in the sense of being averse to big new programs or dramatic change. For example, Rep. Stephanie Murphy’s (D-Fla.) recent comments suggest that she thinks Biden and Democrats are trying to do too much, too fast, and that bothers her more than her objecting to any particular part of the bill. Manchin, in particular, is ideologically more conservative than most Democrats, so he is wary of expansions of government that sound liberal (like a child tax credit going to families where no adult has a job) and provisions that seem anti-business (the numerous tax increases on corporations and the wealthy in this proposed legislation) even if they are popular.

Second, many of these members define themselves as independent from the Democratic Party, particularly its left wing. In the late 1980s and early 90s, there was a centrist policy wing of the Democratic Party that pushed ideas such as welfare reform and charter schools, but many of today’s centrist Democrats are more clearly defined by what they are against — the ethos and ideas of Democrats such as Rep. Alexandria Ocasio-Cortez (N.Y.) and Sen. Elizabeth Warren (Mass.). The strong support of this reconciliation bill by Democrats such as Warren and Ocasio-Cortez likely makes it suspect to someone like Sinema, whose brand is partly rooted in being hostile to the party’s left-wing. And while Biden is more moderate, he is the embodiment of the Democratic Party, which Sinema also wants to keep some distance from.

Third, there is careerism. Members of Congress who either don’t win reelection or choose to retire often seek jobs in lobbying or finance. Blocking parts of a bill that would have hurt a powerful industry is a great credential for a job in that industry.

Fourth, there are electoral reasons to oppose a bill even if it’s popular with the broad public. The distance from the party that members like Sinema cultivate by bucking the Democrats’ goals might be more electorally valuable, particularly in terms of wooing swing voters, than supporting even fairly popular ideas. Some of these members get a lot of campaign donations from industries (like Wall Street in the case of Rep. Josh Gottheimer (D) of New Jersey) that might be weakened in this bill. Other moderates might want to avoid having a lot of industry campaign donations going to their opponents. For example, legislation that makes prescription drugs cheaper for consumers, as this reconciliation bill would do, in effect takes money away from pharmaceutical companies. Becoming an enemy of the pharmaceutical industry could be bad electoral politics for a member in a swing district.

Also, even if Biden’s stimulus and reconciliation bills are both individually popular, there is a case that more centrist voters will see a $1.9 trillion stimulus package and a $3.5 trillion (over 10 years) reconciliation package being passed on a party-line basis as too much for one year. I don’t find this case persuasive myself, particularly if the alternative is not passing much of anything. But Manchin always positions himself as the reasonable man between two unreasonable poles — and he’s one of the most effective vote-getters in politics, winning regularly in a state that skews heavily Republican. Their behavior suggests that moderates like Manchin and Sinema are wary of Democrats being perceived as overreaching.

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Here’s the big problem with those explanations of the centrists’ behavior: They are not great explanations for the centrists to give in public. The centrists’ stated explanations for opposing the reconciliation bill, like Manchin suggesting the bill would heighten inflation, don’t make sense. But Manchin would be mocked if he said that he opposed the reconciliation bill simply because he thinks Democrats just shouldn’t pass a lot even though they have total control in Washington. No member of Congress can openly acknowledge that they fear the electoral power of big corporations or want jobs from them after they leave Capitol Hill. Sinema may not herself even be fully conscious of the fact that she would like a bill less, no matter its contents, if Ocasio-Cortez came out in favor of it.

That all ends up producing a debate that is both odd and tense: Progressive Democrats increasingly fume publicly at the moderates, casting them as “corporate Democrats” in the pockets of big companies. Moderate Democrats make vague or misleading arguments about their opposition to the bill. And the Biden administration and congressional Democratic leaders aren’t quite sure how to get the moderates on board.

And where do we end up? What I expect to see is Democrats eventually settling on a $1.5 trillion to $2.5 trillion bill that cuts out a lot that progressives like. That would accomplish three goals of more moderate Democrats: making the bill less disruptive, less antagonistic to big industries and less pleasing to the party’s left.

And if that’s what happens, it will be another illustration of what I think is already fairly clear about the Democratic Party: It is divided, but in more complicated ways than the popular narrative. Contrary to the conventional wisdom, the left often supports ideas that poll well — and it’s the moderates who often don’t.