Democrats’ problems right now are bigger than Biden’s declining job approval. Polls can change, after all. What’s scary to them is the fact that most of the things that are driving his decline aren’t easily amenable to policy changes, which means the party is largely a prisoner of events outside of its control. COVID will do what it will do; Biden’s vaccine mandate might help hold down the spread but the course of the pandemic is largely out of his hands. (Although a big ramp-up in cheap tests might go a long way towards mitigation.) Supply-chain issues are also something he can only tinker with at the margins, as that’s a global problem that’ll ultimately need to be solved by the market.

The one potential gamechanger that’s fully within the party’s grasp is infrastructure. They could make a deal on the reconciliation component at any time, sending that bill rocketing through the Senate and then the House and handing Democrats an enormous victory to show off to voters.

But there’s a grim possibility for lefties there too. What if they pass something and … it’s not a gamechanger? What if the public largely shrugs or, worse, the size of the reconciliation bill end up pissing off one wing of the Democratic Party or another? If Manchin and Sinema cave and Dems end up with a $3.5 trillion mega-bill, moderates will sweat. If Manchin and Sinema hold fast, which is likely, and shrink the bill to half that amount, progressives will spend the next year complaining that they blew their chance to get everything they wanted.

It’s conceivable if not likely that Biden and Pelosi are going to get something done and the public, including a meaningful number of voters from their own party, will be less happy afterward than it is now.

What do Dems do then? They’d better start thinking about it in case this CNN poll is accurate, because, er…

That’s not a disaster for them depending on how the percentages shake out demographically. If all of the people who think the bill will make them worse off were voting Republican anyway then Dems aren’t losing anyone by passing it. And if all of the people who think they’ll be better off were lukewarm progressive voters who’ll now be motivated to turn out next fall then Dems have gained something. But 25 percent is a meager result for a party that draws 50+ percent of the popular vote in national elections. It’s not just marginal Dems who believe the infrastructure package won’t benefit them much either. Per CNN, that cohort includes “several groups critical to Democratic electoral success, including independent women (59%), Black people (58%), those younger than age 35 (54%), Latino people (51%) and moderates (50%).”

Voters, even core Democratic voters, just don’t think the party’s big achievement will matter much to their lives. Is that a salesmanship problem, maybe? Pelosi wants us to think so. Maybe if Dems took Tim Miller’s advice and boiled these leviathan bills down to a few bullet points — paid family leave, child tax credit, lower prescription drug prices — Americans would be more excited.

But it’s also possible that the “progressives versus centrists” drama in Washington has created a political dynamic among the Dem base in which one faction or another is now destined to view reconciliation as a defeat no matter what ends up passing. Just ask House progressive leader Pramila Jayapal, who seems to prefer tanking the whole package if she can’t get her way:

Rep. Pramila Jayapal D-WA addressing supporters about budget reconciliation in a virtual event tonight:

"A lot of people have asked, isn't something better nothing? And the answer, quite simply, is no."

— Jamie Dupree (@jamiedupree) October 13, 2021

How divided are Democratic voters on the size of the bill and the knife fight between lefties and centrists over it? Almost as divided as can be, per CNN:

Note the split in the second question below, which surveyed Democrats and leaners exclusively. Around a third of Dems think Biden should be backing up progressives while slightly more than a third think he should be backing up moderates. No matter what he ends up doing, he’ll piss off a huge chunk of his own base:

It gets worse. Thanks to Manchin and Sinema, the final reconciliation bill is destined to be vastly smaller than progressives prefer. But CNN’s data suggests that most of the party’s voters — 75 percent, in fact — want to go big on reconciliation. If that’s true than three-quarters of all Democrats are destined to be dissatisfied with the final product:

Want to make it even more complicated? CNN found 36 percent of independents want to go big on reconciliation. But 32 percent want a smaller bill, which is the likely outcome, while another 32 percent want nothing to pass. It seems likely that a majority of indies will end up disappointed no matter what Democrats end up doing.

It’s even possible that CNN is overestimating support for the Democrats’ plans altogether. They have Biden at 50 percent approval in this poll, considerably higher than what most other pollsters have seen lately. What if the real-life share who believe that the infrastructure package will improve their lives is even lower than 25 percent?

And don’t forget, a smaller topline number on the reconciliation doesn’t just mean less spending. It means some programs in the bill being scaled back and others being dropped entirely, which will infuriate the many discrete constituencies those programs have within the Democratic coalition. A lot of activists are going to be left at the altar by Biden and Pelosi at Joe Manchin’s insistence. How do you think they’ll react to the bill’s final passage? With a parade or with a sustained grievance session about how the party missed its big opportunity and won’t have another for years?

This is what happens when you have a broad coalition with a lot of moving parts, I guess. The GOP’s task is comparatively easy: Their goal is to stop the Democratic agenda and Republicans of all stripes can and will usually unite around that shared goal. Democrats actually have an agenda to enact and the centrists in their caucus are forcing them to make sacrifices in the name of what’s politically and fiscally feasible. That means many liberals will be disappointed and demotivated once the infrastructure process is done. That doesn’t smell like a meaningful, gamechanging victory to me.