There are plenty of arguments against a bill in the California legislature that would exempt California teachers from taxes on their salaries.

But forget those arguments about the cost, about the fairness of exempting people who make more than the median Californian from taxes, or even about the problem of public employees forgoing paying certain taxes that fund the governments that support them.

Let’s ask a question: what do we get in return?

The answer, according to this bill, is nothing new. Well, the argument is that more teachers will stick around, and there’s supposedly a teacher shortage in the state. But that’s not good enough.

Instead, it’s more of the same problem in California. We Californians keep paying more, and getting less.

I’ve written about this phenomenon before. The most recent example is in education. We voters approved Prop 55 last year to extend taxes—and now many school districts are facing cuts (in no small part to cover higher pension contributions for teachers). Another common problem: when funding for schools does go up, the money ends up in salaries – not in better or additional instruction.

So if teachers want more, great. They have a tough and important job. But so do other Californians. And so do our kids, trying to learn at schools with insufficient funding.

Here’s the price I would suggest. Make the income tax break conditional on extending the school year by 4 weeks – so that every kid in California gets 200 days of school. Teachers must accept this without a pay raise—their compensation would be the income tax exemption.

It’s only fair. If teachers want to shift the costs of government onto the rest of us, then they need to teach more.