By JAMES TARANTO

They told us that Americans would learn to stop worrying and love ObamaCare. To judge by yesterday’s election in Missouri, they were wrong.

Official election returns show that citizens of the Show Me State voted overwhelmingly–71% to 29% in favor of Proposition C, a ballot measure described in a pre-election report from Time magazine:

“The specific issue boils down to this: Can the government require that citizens buy health insurance? Mandatory insurance is a key element of the health care reforms passed by congressional Democrats and signed by Obama this year. Adding healthy people to the insurance pool spreads the cost of policies for people with health problems. Missouri’s referendum rejects that mandate by asking voters whether state laws should be amended to forbid penalties for failing to have health insurance.”

Time describes the vote as “largely symbolic.” Other states have already passed such opt-out laws via legislative action rather than voter initiative, and the real test will come in the courts. But symbolism matters. If the constitutional question is a difficult one, it’s possible that judges will resolve it on the side of public opinion. And of course the public’s reaction to ObamaCare is likely to influence the politicians who have control over its implementation and possible repeal.

Time tries in advance to minimize the expected result:

“Tuesday’s primaries are far more interesting on the GOP side, practically guaranteeing a turnout heavily skewed against health care reform. . . . Democrats in the Missouri legislature had consciously maneuvered Prop C onto the August ballot. The argument was that it would be better to hold the referendum this month than let it become a rallying point for the GOP in November, when retiring Senator Christopher “Kit” Bond’s seat is up for grabs.”

“Far more interesting on the GOP side” is an exaggeration. Both party’s Senate candidates won with more than 70% of the vote, and Missouri is not electing a governor this year. We suppose it’s possible that Republican voters were drawn to the polls by the thrilling contested race for state auditor and cast ballots against ObamaCare as an afterthought. More likely, though, it’s the other way around. And in fact, the number of people who cast ballots on Proposition C was more than 100,000 greater than in all parties’ state auditor primaries combined.

Time provides further evidence that ObamaCare support is hazardous to political health. Democratic Senate nominee Robin Carnahan, whose brother Rep. Russ Carnahan voted for ObamaCare, could muster only a “lukewarm statement” of–well, we guess we’ll be generous and call it support:

The statement by spokesman Linden Zakula was cryptic: “If the issue is approved by the voters, there is some question about what would be the practical implication since it would be an issue of state law pre-empting federal law. But when it comes to this issue in general, as a breast-cancer survivor [Carnahan] takes the issue of health care very personally, and thinks it makes a lot more sense to fix the things that still need fixing instead of repealing the entire bill, or opting out, and going back to insurance companies making out like bandits and denying coverage for people with pre-existing conditions.”

Another possibly ominous sign for Democrats in the Obama era: Carnahan’s opponent, Rep. Roy Blunt, received nearly 410,000 votes in his essentially uncontested primary. She got just 265,000 in hers. (Missouri has an open primary, so that anyone can vote for either party’s candidate.) This is thought to be a toss-up race, with Blunt, who served as House Republican whip for three terms starting in 2003, a less than ideal GOP face in an “anti-incumbent” year.

Meanwhile, Time reports that other states will have ObamaCare opt-out measures on the ballot in November. If yesterday’s results in Missouri are any indication, Nov. 2 could be a long night for congressional Democrats–and for the White House.