Enrollment is the key to many of Baltimore City schools’ problems. Declines in the last few years have put pressure on the budget; each lost student means more than $11,000 in reduced aid from the state. That forces a negative spiral of budget cuts and more enrollment declines. Growing enrollment, on the other hand, could have the opposite effect, making underpopulated schools more efficient and enabling them to provide better opportunities for students.

As such, it was heartening to see the Baltimore City Teachers Union spearhead (and mostly fund) a summer-long recruitment drive in which educators are going door-to-door to find children who have stopped going to school and re-enroll them or to convince parents who might otherwise send their children to private or parochial schools or move to the suburbs to give city schools a chance.

We offer an additional suggestion that, given the last half-century of local history, might seem like a radical idea: Don’t limit the recruitment efforts to kids who live in the city. For all their challenges, Baltimore schools offer some opportunities that suburban public schools don’t. If some parents from the counties were persuaded to send their children to city schools, it could benefit them with educational models that better suit their needs, it could help existing city students by fostering more socio-economic and racial integration, and it could help secure the district’s finances.

The model already exists in the Baltimore School for the Arts. That renowned institution draws about a quarter of its students from outside the city, as far away as Washington, D.C. Those families are actually paying tuition for their students to attend pubic school in Baltimore City. A handful of others are doing so at other city schools, most of them at Western High School. That makes sense; if you want an academically rigorous all-girls school, it’s still a steal.

But BSA and Western aren’t the only city schools that might present families with better opportunities than they can find in the suburbs. Both City College and Baltimore Polytechnic Institute beat the Baltimore County average on every PARCC test last year, and Poly, in particular, crushed it.

In addition to its traditional selective high schools, Baltimore is piloting a number of attractive new educational models, such as the Pathways in Technology Early College High Schools and Bard Early College High School, both of which allow students to graduate with high school and associate’s degrees.

Baltimore’s profusion of charter schools offer a variety of other educational models and programs that suburban schools don’t. They already attract students from across the city; why should that opportunity end at the county line?

There are a couple of obvious objections. One is that it seems wrong to give slots in such programs to kids from the suburbs when many city students face great disadvantages. But wide bodies of research over decades have shown that racial and economic integration has massive educational benefits for such students. The other issue is the money. How many parents would be willing to fork over $6,510 a year to send their kids to public school? Last year in Baltimore, all of nine, other than those at BSA.

We ask, why should they have to? Tuition is perhaps justified in the case of BSA, given the unique costs of its program, but Baltimore needs kids in desks. It doesn’t matter, fiscally speaking, if they live in the city or the counties.

As The Sun’s Liz Bowie reported in her series this year on segregation in the schools, Hartford, Conn., draws students from across the region to innovative schools under a court order in what is considered a national model for desegregation. Dallas, Texas, is doing something similar with new schools that reserve a portion of their seats for middle- and upper-income students, including some who live outside the district. Given the Baltimore region’s politics, that might be impossible to achieve absent a court order, but city schools could at least start by dropping the tuition requirement, opening the doors and inviting all who want to come.