Just like that, in less than a month the so-called pension “reform” plan being pedaled by Los Angeles’ mayor from the 1990s Richard Riordan fizzled and died.

Riordan announced last week that he’d stopped trying to gather signatures to put his unstudied, untested idea on the ballot. So, the idea likely won’t amount to more than a blip in the news cycle. However, California’s other cities ought to pay attention. The warning: ill-conceived, politically motivated, non-bargained pension changes are a costly and tough row to hoe.

Just look at San Diego. Voters there OK’d a pension overhaul in June but its implementation has been much messier. Six months after the vote the city is still struggling to put the “reforms” in place. The city has sued the state over a piece of legislation that conflicts with its Proposition B.

In San Jose, Mayor Chuck Reed won a lot of headlines for his attempts to refurbish his city’s pension system, but its Measure B is tied up in court as well, and can’t be put into effect.

Reforming pensions at the ballot box hasn’t worked. Even the nonpartisan Legislative Analyst’s Office said, at the state level, that proposed pension changes made through the initiative process were likely to cost governments more, not less, over the coming few decades.

The right place to negotiate pension changes is at the bargaining table. More than 240 local unions throughout California have already recognized that they must make concessions in this difficult economy — and have done so through bargaining. On top of that, Governor Brown’s reforms begin in January, reducing the compensation of the state’s teachers and employees in more than 1,500 local governments by $60 billion.

If local elected officials are smart, they won’t let Riordan’s efforts be fizzled and forgotten; they’ll learn this lesson: pensions changes are best made at the bargaining table, not in the ballot box.