Of all the questions candidates for governor are asked, none are more important than the ones dealing with Maine’s most vulnerable populations — the very young and very old, the infirm, the impoverished. Add to that list the people dependent on Maine’s mental-health system, which has undergone significant change in the last four years yet remains well short of unqualified success.

The Northeast Networking and Support Group, an alliance of this region’s mental-health organizations, not long ago asked the candidates five questions concerning mental health. Two candidates — Republican Jim Longley and Taxpayer Bill Clarke — answered succinctly by not answering at all. Green Pat LaMarche offered a few quick notes in response. Gov. Angus King and Democrat Tom Connolly answered at some length. Of course candidates are sent an overwhelming number of questionaires and surveys seeking their positions, but that’s what campaigning is all about. The choices candidates make about which request to respond to say a lot about their priorities.

Access to the state’s mental-health system is likely to be a controversial issue again this winter in the Legislature. Under Commissioner Melodie Peet, the mental-health system has tried to become more responsive to the backlog of cases even as the number of long-term hospital beds in Bangor and Augusta have been reduced. The chronic lack of a comprehensive system can be seen in Maine’s prison system and its homeless shelters, where the mentally ill often end up.

Part of the source for the challenges confronting the mental-health system are entrenched in widespread attitudes regarding mental illness and in budgetary realities that often require incremental improvement rather than all-out change. On a Northeast Networking question about Maine children being treated out of state, Gov. King’s in-depth reply noted that, “it is clear to me that sending children out of state for mental health treatment is a symptom of the larger problem that we had a fragmented system of services, with no single point of authority or accountability.”

That sums up the problem neatly, but it is too easy to describe it as a problem Maine “had” rather than one that continues to exist in a less-extreme form. Certainly, out-of-state referrals for the mentally ill generally have not gone away.

From his response, Mr. Connolly seems to understand the issues around mental health. His interest and emphasis on outreach programs for children in rural areas is worth studying. As an attorney, he correctly sees the problem of “dumping and non-accountability by the state for its mental health obligations by its impact on the criminal justice system.”

The questionaire didn’t ask candidates to describe in detail how they would fix problems in the mental-health system. Just getting candidates to think about the problem is challenge enough.