The strong desire to retain local control over the management of the county school system expressed this week by Superintendent Barbara Canavan is one of those general sentiments it's easy to agree with.

Get into the specifics, though, and reality creeps in.

Most people are all for local control until they disagree with the local people in control. Then they go to their state delegate or member of Congress or some other person elected to an office that isn't particularly local.

Likely as not, the issue prompting Canavan's concern grew out of a county school board in Maryland making a decision about starting the school day "too early" or dismissing students "too late" that irritated people in that county, and state legislators were called. Regardless of the motivation, the Maryland General Assembly is ordering the state health department to conduct a study of what the most healthful times are for classes to begin and end, and issue a report in time for the start of the next legislative session.

There's related matter that precludes the school system from ever having absolute local control: money. Very roughly speaking, about half of the school system's budget comes from the state government and about half comes from the county government, plus a sliver of the funding pie comes from the federal government and so-called other sources.

In Maryland, school systems don't have the authority to levy taxes, so local boards of education are beholden to the state and county governments, to some degree, on just about any issue. The school system's boards and administrations, however, are allowed a lot of autonomy with regard to how they spend the money allocated by their counties and the state. The result is a semi-adversarial relationship that forces review of decisions made at the local level by the school system, as well as decisions made at higher levels and passed down, sometimes much to the irritation of people at the local level.

In short, it's good and healthy for Canavan to advocate for local control, but the local school system will never have absolute control. That also is good and healthy because it puts in place something that is vital to the functioning of a free society: outside checks and balances.