Are Democrats repeating their Obamacare mistakes?

If you leave milk out for too long, it curdles. If Democrats aren’t careful, they are about to let this happen with their big and broadly popular investment program, just as they did a decade ago with Obamacare.

Over time, the Affordable Care Act became popular enough that Republicans couldn’t repeal it even after they won the power to do so. But in the years immediately after the ACA passed, the bill was tainted by a protracted and ugly legislative process that left voters wondering.

And soon after, Democrats lost the House in the 2010 midterm rout.

Let’s stipulate that much of the ugliness in Washington now is the product of a Republican Party whose level of irresponsibility is boundless.

Playing chicken with the country’s credit by disclaiming any obligation even to allow Democrats to hold an up-ordown vote on raising the debt ceiling is disgraceful. There’s also the matter of the GOP undermining the democratic process itself in state after state.

Unfortunately for President Biden and Democrats who hold the narrowest of congressional majorities, this only increases the burden on them to prove that the system can still solve public problems.

Democrats got off to a good start with the content of the two big bills they are trying to push through. They married the desire for fundamental change among the party’s large progressive wing with a set of specific programs that, taken individually, are anything but radical.

The Build Back Better plans for child care, elder care, housing and health coverage largely build on ideas that have already been tested successfully in many states and other democratic nations. And the United States will have zero credibility in encouraging the rest of the world to deal with climate change if Biden’s carbon-reduction proposals are left to die.

Passing these initiatives, along with a bill for physical infrastructure that many Republican senators voted for, would be an achievement that politicians could brag about for a generation.

But Democrats have a gift for never making things simple.

Some of the trouble comes from how hard agreement can be in a philosophically diverse party that makes room for democratic socialists as well as moderates who could once find a home in a less radical GOP.

And I still believe what I wrote a few days ago: that the vast majority of Democratic senators and House members do not have a death wish.

The problem is that two moderates are prolonging the process of coming to closure. Sens. Joe Manchin III, D-W.Va., and Kyrsten Sinema, D-Ariz., keep talking to Biden without saying specifically what they want.

In times of turmoil, I often turn to Rep. David E. Price, D-N.C., who doubles as an experienced lawmaker and a political scientist whose book “The Congressional Experience” is now in its fourth edition.

“Senators Manchin and Sinema have an obligation to the rest of us to state their position,” Price said. “It’s impossible for us to negotiate if they don’t either give a top-line number or say what they want to cut. But if they do provide that, it’s then an obligation of progressives to show some forbearance, to support the physical infrastructure bill — which we should be proud of — and then negotiate on the larger bill.”

This is the only way to keep what began as a bracing effort at social reform from turning terribly sour.