THE RECENT opinion piece published in CommonWealth on the judiciary’s illegal adoption of new sentencing guidelines was a muddle in need of clarification.

The writer, identified as a former assistant attorney general and legislative staff member, does an artful and convincing job of defeating an argument that no one, anywhere in the debate, has raised. She creates and defeats the straw man in one deft sentence:  “Seven of our district attorneys are contending that it’s unconstitutional for judges to use sentencing guidelines in an advisory capacity when the US Supreme Court has ruled that sentencing guidelines are constitutional only when they’re used in that capacity.”

No district attorneys have argued any such thing.

There is no dispute that the guidelines were always meant to be “effectively advisory” – the title of the relevant section of the law is “Recommended sentencing guidelines.” We do argue that the word “shall” holds the same meaning in Chapter 211E, which governs the sentencing commission, as the meaning it holds in every other use in the Massachusetts General Laws.

Chapter 211E of the Massachusetts General Laws says the sentencing commission “shall recommend sentencing guidelines, which shall take effect only if enacted into law.”  They are not adopted when the commission decides, not when the DAs decide, not when the judges decide, but when they have been submitted to the Legislature, vetted through that branch, and passed into law.

We argue that the judiciary has no more right to usurp the legislative function than the Legislature has to usurp judicial purview.

We argue that the separation of powers doctrine which has given us centuries of stable democracy should not be put aside for expedience.

This is not a matter of nuance or interpreting federal rulings. If legislative staffers do not know the legal meaning of “shall” at the start of their first day working in that building, they know it by the end of that day.

This democracy has survived for centuries because we have a carefully crafted balance of power between the branches. It is dangerous for partisans, however well meaning, to abandon that principle when it is expedient for their beliefs.

This is not the time in our history to freely give away that priceless legacy of our democracy.

Michael W. Morrissey is the district attorney of Norfolk County.