St. Louis Circuit Attorney Jennifer Joyce proposed last week a discrete but significant exercise in regionalism: St. Louis and St. Louis County should merge their jury pools.

Ms. Joyce is on the right track. But she should think bigger.

City residents do more than their share of jury duty. The volume of criminal cases in St. Louis circuit courts and the frequency with which defendants demand a jury trial mean city residents are called to serve every two to three years.

Their suburban counterparts, according to Ms. Joyce, can go the better part of a lifetime never being called.

Broadening the pool would spread the burden of jury duty more equitably throughout the region. (Some would argue it also would ease her job as a prosecutor, given that suburban jurors generally are more trusting of law enforcement and thus more likely to convict in criminal cases.)

Her proposal came amid expressions of worry about public safety: the recent rise in violent crime; the failure of myriad public agencies to intervene on behalf of children headed for trouble and heavy turnover of experienced prosecutors who owe a great deal of money in student loans and can earn more in private practice.

There is a common thread running through all these concerns:

Crushing demands on one part of the criminal justice system can degrade public safety in a much larger area. City and county residents have a shared interest in a strong and efficient regional criminal justice system because crime and disorder do not respect political boundaries.

The St. Louis region would benefit not just from combining jury pools but also from a grand merger of county and suburban courts, prosecutors and police departments. Many potential advantages come to mind: less duplication of effort, better and more flexible use of resources, better policing and potentially, a far safer region.

On the other hand, think of the turf battles. Think of the outraged screams of some suburban residents who would see some of their tax dollars flowing to police and courts in urban areas. Think of the hostile reaction such a proposal would receive in the Legislature. Just because a proposal makes sense doesn’t mean it makes good politics.

Still, there are plenty of things Ms. Joyce and St. Louis County Prosecutor Robert McCulloch could work on — prosecutor to prosecutor — that could make a difference without a dramatic reordering of the political landscape.

Ms. Joyce points out that she and Mr. McCulloch already collaborate. Both are members of a state prosecutors association and work together on legislative issues. They coordinate well on multi-jurisdictional crimes. Their employees participate in joint training programs.

That’s good for starters. What else can they do?

How about establishing a pool of experienced prosecutors from both offices — cross-deputized and available to try serious felonies in either jurisdiction, sort of a prosecutor’s version of the police Major Case Squad? That way each office could help the other on tough cases and ensure that neither is caught short of top lawyers.

Student loan costs make it difficult to recruit and retain top law school graduates, not just among prosecutors but also in all kinds of public-interest law practices, including public defenders and legal aid lawyers.

The public sector can’t compete with private law practice when it comes to salaries. But what about a program — funded with a combination of public dollars and private philanthropies — to help talented young lawyers pay off their student loans in return for few years of public trial work?

Ms. Joyce and Mr. McCullough should consider a joint planning process, perhaps in concert with other regional prosecutors and professional organizations. By exploring different ways to work together, they might well make the justice system work better and make the rest of us safer in the bargain.

(A video slide show of Ms. Joyce’s interview on The Platform can be seen here.)

Note: An early version of this editorial was edited to correct the spelling of St. Louis County Prosecutor Robert McCulloch’s last name.