Joe Biden’s domestic agenda at the moment is, like his presidency, in peril.

It is caught between the Scylla of progressives insisting the bipartisan infrastructure bill can’t pass the House before the reconciliation bill passes the Senate and the Charybdis of moderates insisting the bipartisan infrastructure bill must pass the House before anything else happens.

It is, to switch metaphors, an old-fashioned Mexican standoff, with the intervention that will lead to all factions holstering their weapons not yet evident.

Still, the conventional wisdom is that Democrats will get both bills in the end. They will stare into the abyss, recognize the party-wide debacle that would ensue if they pass nothing, and agree, somehow or other, on the infrastructure bill and a reduced reconciliation bill.

It’s certainly true that, whatever the intervening drama, must-pass spending bills always pass. But the possibility of a complete meltdown shouldn’t be underestimated.

The reconciliation bill isn’t too big to fail, but big enough potentially to fail spectacularly. It has the hallmarks of other signature presidential initiatives that, despite huge investments of presidential political capital, have gone down at the hands of a president’s own party.

In an unimaginable defeat at the time, Bill Clinton couldn’t get his health-care bill through Congress, despite a roughly 80-seat House majority and 56 or 57 senators.

After his reelection in 2004, George W. Bush’s Social Security reform fizzled in a GOP Congress.

Out of the gate, Donald Trump suffered an embarrassing defeat on Obamacare repeal in 2017.

So, no, victory isn’t inevitable, no matter how much Biden needs his bills.

It is a well-established axiom that delay, which especially characterized the Clinton health-care debate, is a killer. Presidents don’t tend to get more popular after an election, and if a delay pushes a fight into a midterm-election year, members of his own party are likelier to conclude that they need to go their own way to protect their interests.

This is why Senator Joe Manchin’s talk of putting off consideration of the reconciliation bill until 2022 is itself an existential threat to its prospects.

It’s always a warning sign when a specific, party-wide electoral mandate hasn’t been built for an agenda.

Clinton didn’t set out in any detail his ambitions on health care during the 1992 campaign. Bush hardly campaigned on Social Security reform. And Trump had no idea about what would replace Obamacare.

Biden did lay out his agenda last year, but he never made it front and center in the campaign. Instead, he presented himself as the anti-Trump who would bring the country together.

Obviously, the size of congressional majorities matters. Clinton and Bush couldn’t work their will despite healthy numbers, whereas Trump had a very slender majority in the Senate, opening the way for John McCain’s famous thumbs-down.

Biden technically doesn’t even have a Senate majority. This gets to what sets him apart from all of his predecessors — the massive disconnect between the scale of the legislation he seeks and the narrow majorities that are supposed to pass it.

There’s a hunt for villains among progressive commentators as the Biden agenda encounters turbulence. But why wouldn’t a president who has an approval rating in the mid 40s, a tie in the Senate, and a single-digit majority in the House have difficulties passing the most sweepingly ambitious progressive agenda in decades?

The Democratic factions are empowered to make their conflicting demands because the margins are so small.

The bill is so huge — with everything stuffed in it to avoid the filibuster — also because the margins are so small.

Given the real risks of failure, it would make sense for Democrats to pass the infrastructure bill and pocket that success, then move on to reconciliation, realizing one way or the other that it is going to be slimmed down.

Yet that’s not the Democrats’ mood right now, even though history says that they should be afraid, very afraid.

© 2021 by King Features Syndicate