But here goes.

A new study concludes that the rules adopted by the Legislature for commercial property sales have had the effect of shifting the tax burden to residential property owners. The California Tax Reform Association says changing those rules would produce millions of additional tax dollars for schools, police and fire protection and other local services that have been cut time and again — without any impact on taxes paid by homeowners.

Here’s why: Under Proposition 13, residential property taxes are straightforward. When a house is sold, the tax bill is fixed at 1 percent of the sale price with increases limited to 2 percent annually. The formula is written into the state constitution and can be changed only by the voters.

If a business property changes hands in a single transaction with a single buyer, the same rules apply. But if no one buys a majority interest all at once, the property tax base remains unchanged. Most business deals are structured to avoid a reassessment. Among the examples cited in a recent legislative report was the 2002 sale of Louis M. Martini Winery to E&J Gallo, which would have resulted in $700,000 a year in additional property tax revenue, mostly in Napa and Sonoma counties, if not for the special treatment of commercial property sales.

According to the Tax Reform Association report, the commercial share of property taxes has fallen in nearly every California county under the post-Proposition 13 rules. In Sonoma County, for example, commercial property owners pay 27 percent of property taxes, down from 34 percent in 1984. In Lake County, commercial property owners paid 44 percent in 1972 and now pay less than 25 percent.

The commercial real estate rules were written by the Legislature, and a bill by Assemblyman Tom Ammiano, D-San Francisco, would broaden the definition of a sale to include any transaction in which 100 percent of a property changed hands, regardless of the number of new owners.

The biggest beneficiary of any additional revenue would be public schools. Smaller shares would go to cities and counties. The recession (and state raids) have forced local government to make big cuts. At times, we’ve called for bigger cuts. But fairness is a consideration on the revenue side of the ledger, and that includes the tax treatment of property sales.

Republicans in the Legislature oppose Ammiano’s bill, siding with the California Taxpayers Association, which represents major commercial interests and contends that the labor-backed Tax Reform Association study is biased.

Ammiano’s bill needs a two-thirds majority, so Republicans can block it. But the issue is worth exploring. Perhaps as an interim measure, a nonpartisan examiner such as the state legislative analyst could assess the Tax Reform Association’s numbers.