A handful of centrist Democrats issued a stark threat on Friday morning: If the House does not hold an immediate vote on the bipartisan infrastructure bill that passed the Senate, they will withhold support for a procedural measure that’s necessary to pass the larger reconciliation bill.

Let’s be clear: This is a threat to tank the entire process that has been carefully constructed to ensure that President Biden’s full agenda makes it to his desk.

This underscores just how careful a balance Democrats must strike to keep their coalition together to ensure that Biden’s agenda becomes law. It also shows what a tremendous feat it will be if they can pull it off.

The threat came in a new letter from nine centrist House Democrats to House Speaker Nancy Pelosi (D-Calif.), which lays out demands for how the process should unfold from here.

“We will not consider voting for a budget resolution until the bipartisan Infrastructure Investment and Jobs Act passes the House and is signed into law,” reads the letter, which is led by Rep. Josh Gottheimer (D-N.J.) and signed by other members of the House Problem Solvers Caucus.

The “budget resolution” is what the House must pass to lay the groundwork to eventually pass the $3.5 trillion reconciliation bill that Senate Democrats are now assembling. The bipartisan bill is the $1 trillion in “hard” infrastructure that recently passed the Senate.

So this is a threat to scuttle the process needed to pass the “human” infrastructure bill — including big investments in combating climate change, supports for children and families, expanded health care, and much more — to force immediate passage of the “hard” infrastructure package.

This would completely disrupt the two-track process that Biden and Democratic leaders want. Under it, Pelosi will delay House passage of the bipartisan bill until the Senate sends over the reconciliation one, then hold votes on both. This locks in each side: Moderates back the reconciliation bill to get progressives to back the bipartisan bill, and vice versa.

This move by centrists makes zero sense. First, as a Democratic aide pointed out, even if the House did vote on the bipartisan bill today, it wouldn’t pass, because the votes are not there without completion of the reconciliation bill.

That’s because progressives wouldn’t vote for it. So Pelosi all but certainly will not hold this vote.

The centrists seem to believe that if they exercise their leverage in this fashion, it will force Pelosi’s hand. But even if it did, why would it force the hand of progressives?

Second, note that only nine centrist Democrats signed the threat. The names of many, many other Democrats in the Problem Solvers Caucus are not on the letter.

What’s more, even some moderates think this misguided strategy could scuttle the whole process.

“The important thing to me is to get both bills passed and to the president,” Rep. Tom Malinowski, a moderate Democrat from New Jersey, told me. “I fear that forcing a vote now would undermine, not advance, that goal.”

This is correct. The only way to make this work is to make both factions happy at the end of the day.

The charitable view of the centrist position is that it’s a political imperative for them to campaign in their districts solely on passage of a bipartisan bill with “hard” infrastructure, one that isn’t tangled up in the politics of the reconciliation bill, which is associated with House progressives.

I think progressives should be more sensitive to the political challenges that moderate Democrats face in difficult districts, and refrain from attacking them as squishy sellouts every time they express reservations about the politics of any given thing.

But even if you accept this view, in this case these centrists are asking for too much. Every time they make a threat like this, it seems more obvious that they will indeed withhold support for the reconciliation bill later, or at least insist on dramatically downscaling its spending.

Which only reinforces the need to stick to the two-track strategy.

It’s true that under the two track strategy, centrist Democrats will not get to campaign on passage of the bipartisan bill in isolation, as they want. But it’s also true that progressives will not ultimately dictate what the reconciliation bill looks like.

The latter will have to satisfy Sens. Joe Manchin III (D-W.Va.) and Kyrsten Sinema (D-Ariz.), not to mention the House centrists as well. That bill will ultimately spend less than $3.5 trillion, and progressives will have to accept some of those concessions.

Neither side will be fully happy with the end product. And that’s how the two-track strategy is designed to work. Disrupting it now over a desire to see this unfold in a different procedural order makes no sense.

At the end of the day, what’s at issue is the Biden agenda and the Democratic Party’s agenda. The combination of the two bills would invest large sums in the future of the country, in infrastructure that increases efficiency and worker productivity, creates jobs, and reorients the country toward the climate challenge, while giving a lift to millions struggling to enter or hang on in the middle class.

That’s something both centrist and leftist Democrats can campaign on. Disrupting the two-track strategy threatens to bring that whole agenda down. Holding together makes it more likely that the end product will be a win for everyone.