Was election victory a sign of changing times?

It would be easy to misread Steve Glazer’s victory in the 7th Senate District special election as a dramatic, but isolated, event.

By its solitary nature, a special election gets extra attention. The massive spending, $10 million more or less, adds another layer. And a duel between two Democrats, one backed by unions and the party structure, the other by business, completes the dramatic scenario.

Assemblywoman Susan Bonilla’s loss is certainly an embarrassment for labor and the party commissariat, which are indistinguishable.

But it shouldn’t be a surprise, given the nature of the Contra Costa County-centered district.

Its voter registration is lopsidedly Democratic, but that reflects the cultural liberalism of affluent suburbanites rather than affection for unions. And even its Republicans tend to be of the centrist variety.

Unionism has acquired a particularly bad reputation in the region, thanks to a Bay Area Rapid Transit strike that left commuters stranded and a series of sensational revelations about public pension abuses.

Glazer, a political consultant and local officeholder, understood that Democratic fault line and exploited it quite adroitly. He portrayed himself as independent from union bosses, while appealing to Republicans, who were a third of Tuesday’s voters, and independents.

Bonilla and her backers, meanwhile, pitched only to Democrats, and she would have needed all of them to win.

But that was never going to happen; ergo, she lost by about 10 percentage points.

In the aftermath, the Democratic hierarchy denounced Glazer, saying he “claimed to be Democrat but ran a cynical campaign to appeal to Republican voters in a low-turnout election.”

Presumably, the party and unions will try to unseat Glazer when he seeks a full term next year, counting on a much-higher voter turnout. But it won’t be easy, because Glazer actually fits the district quite well, not unlike the man he replaces, Rep. Mark DeSaulnier, who as a senator often chewed through the party leash.

Will the Senate’s Democratic leader, Kevin de León, who’s close to labor, try to isolate Glazer for his heresy or let bygones be bygones?

Ostracizing Glazer could help him win re-election by proving his claim to be an independent politician, not beholden to union or party bosses.

Marin County’s Marc Levine and Santa Monica’s Richard Bloom, two other Democrats who defeated union-backed Assembly incumbents in 2012 with business support (and Glazer’s indirect help), were not punished in that house.

Their wins hinted that when Democrats duel Democrats in relatively affluent, sophisticated areas, union support doesn’t guarantee victory, and business can engage effectively.

Glazer proved it, and that’s the true import of his victory, given the perpetual war between business and liberal groups, including unions, over so-called “job killer” bills and other legislation.

Dan Walters is a columnist for the Sacramento Bee.