Let’s hope he won’t be baaack with this idea again.

Arnold Schwarzenegger’s “universal” health-care plan died in the California legislature on Monday, in what can only be called a mercy killing. So let’s conduct a political autopsy, because there are important lessons here for the national health-care debate.

It’s especially useful to compare today’s muted obituaries to the page-one melodrama that surrounded the Governor when he announced his plan a year ago. Endless media mash notes were bestowed on the “post-partisan” Republican trying to get something done.

The idea was that Mr. Schwarzenegger would set a national precedent, leading to a groundswell for reform in Washington. Not to mention that the Schwarzenegger plan was a near-copy of the one Mitt Romney pioneered in Massachusetts, and the one Hillary Clinton now favors. A leading author of the California plan was Laurie Rubiner, who directed health policy at the New America Foundation before becoming Senator Clinton’s legislative director in 2005.

But a dose of reality killed it.

An independent analysis confirmed the plan would be far more expensive than proponents admitted. Even under the most favorable assumptions, spending would outpace revenue by $354 million after two years, and likely $3.9 billion or more. “A situation that I thought was bad,” Mr. Perata noted, “in fact was worse.”

This reveals that liberal health-care politics is increasingly the art of the impossible: You can’t make coverage “universal” while at the same time keeping costs in check — at least without prohibitive tax increases. Lowering cost and increasing access, in other words, are separate and irreconcilable issues.

Of course Washington might be able to disregard these practicalities, because the states are prohibited from running deficits while the feds aren’t. But the California experience also reveals some of the ideological differences among Democrats, which would also divide in the Beltway.

The centerpiece of the Schwarzenegger plan was the “individual mandate,” which is also the heart of HillaryCare 2.0. Such a law would compel everyone to acquire insurance, with subsidies for those who couldn’t afford it. But the individual mandate incited a liberal revolt. Many Democrats and some unions argued the subsidies weren’t generous enough to cover lower-income families, and it wasn’t fair to penalize them for coverage they couldn’t afford. One state Senator called the plan “a knife in the throat of the working poor.” So the plan failed because it was too expensive — and because for some Democrats it wasn’t expensive enough.

Opposition also arose because the plan didn’t do enough to punish the left’s health-care villains. While it greatly expanded regulation of insurers — requiring them to accept all applicants, and prohibiting premium differences based on health status — it didn’t cap how much they could charge consumers, or regulate their profits. Democrats also complained that the taxes the plan imposed on business, as high as 6.5% of payroll, weren’t high enough.