With senators set to announce a bipartisan deal on infrastructure, the narrative is already setting in everywhere: The biggest loser is the left. CNN insists that the compromise is “sure to dismay liberals.” Politico snarks that Sen. Bernie Sanders (I-Vt.) is “the loser in this deal.”

But another plausible scenario runs in precisely the opposite way. The movement toward this bipartisan deal could set up an endgame in which progressives end up getting much of what they want — and Sanders ends up getting the last laugh.

Yet importantly, for this to work, President Biden has to get the endgame right. Botching it would be a catastrophe, including for his own agenda and presidency.

The emerging bipartisan deal, which Biden just endorsed, would spend around $973 billion on roads, bridges and other concrete infrastructure, with around $579 billion being new spending. It won’t be paid for with corporate tax hikes (which Republicans despise).

Senators have not announced the pay-fors, but it appears a gas tax hike (which Democrats oppose) is off the table.

This is supposed to represent a big loss to the left because it’s less than Biden originally proposed on concrete infrastructure and doesn’t include the “human infrastructure” priorities in Biden’s agenda — investments in children and families, climate and caregiving infrastructure, etc.

But Democrats are proceeding on two tracks. On one is the bipartisan deal. On the other, Sanders, as Senate Budget Committee chair, is crafting a large package that includes many of those other priorities — this one paid for by corporate tax hikes — and would pass by simple-majority reconciliation later.

By all indications, Sen. Joe Manchin III (D-W.Va.), a lead negotiator in the bipartisan group, is insisting on this deal — or an exhaustive effort at reaching one — as a precondition for supporting a reconciliation package later.

The rub for progressives is that once Manchin extracts his pound of flesh, there’s no certainty that the reconciliation package will ever pass. As Sen. Ed Markey (D-Mass.) puts it, progressives must insist on a “guarantee” that it will happen and will be sufficiently ambitious.

What happens if Manchin and other moderates pull their support or insist on something far too small, stabbing the left in the back?

Amid all the progressive angst, what has been remarkable is how confident Sanders himself has been about this all working out in the end. Why?

Why Sanders is confident

The answer, Sanders aides say, is that in an important sense, he personally functions as the mechanism that, if all goes well, will guarantee that an adequate reconciliation bill passes. That’s because, as chair of the Budget Committee, he has outsize influence over its scale and makeup.

But that’s not all: The committee includes Democratic moderates as well, such as Sen. Mark Warner of Virginia. That puts Sanders in a pivotal position to negotiate something that is sufficiently ambitious and can get the support of 50 Democratic senators. Sanders will inevitably negotiate with Manchin about what this will look like in the end.

Manchin is sending complicated signals about what he might support. He told NBC News that he backs the general idea of passing something via reconciliation that includes human infrastructure and raises corporate taxes in some way.

Yet Manchin also told CNN that he’s wary of too high a price tag on the reconciliation bill. This is where Biden comes in: If a bipartisan deal passes, it will be on Biden to make sure Manchin and other moderates support a robust enough reconciliation package in the end.

Failure would be a disaster for Biden

Could Biden and moderates simply sell out progressives on that front? Maybe. But House Speaker Nancy Pelosi (D-Calif.) told reporters Thursday that the House will not pass the bipartisan bill until the Senate also passes a reconciliation measure, which constitutes leverage to force the latter to happen.

And surely Biden understands that failing on the reconciliation measure would be a disaster for his agenda and presidency.

Biden and Democrats have said over and over that passing a bold agenda is crucial to defusing rising authoritarianism and showing that democracy can deliver for people. Sanders shares this view, and thinks Biden does as well.

“When Biden says delivering material aid for people is key to protecting democracy, Bernie believes he means it,” a source familiar with the Sanders orbit’s thinking told me.

But in the end, Biden has to make this happen. And paradoxically, toward that goal, the perception that the left is taking a big loss could prove useful.

Note that Sanders is quietly giving ground on something moderates want — raising the cap on how much people can deduct in state and local taxes. A draft of the reconciliation plan includes a proposal like this, which will be widely seen as a loss to the left.

All that could allow Biden to tell Manchin and moderates that the left took a big hit with the passage of the bipartisan bill. Biden can then lean on those moderates to agree to something big in reconciliation.

“The senator understands that a short-term victory for moderates actually could open the door more for a reconciliation bill,” the Sanders-orbit source told me.

To be clear, this delicate house of cards could collapse. For instance, if too many on the left balk and refuse to support the bipartisan bill, it could fail, potentially giving moderates a way to refuse to support a reconciliation package.

But that’s a terrible end for everyone, and the pressure will be very great on each element in the Democratic coalition to do its part to avoid this. And if it works out, Sanders and the left could end up being pretty big winners.

The idea that Sanders might be functioning as a canny inside player — on behalf of securing big progressive gains, no less — is hard for many observers to swallow. But it just might end up happening.