Public schools should try to serve every student, but everyone knows that’s not always possible.

Maine’s dropout rate alone shows that no matter how hard teachers try, some students fall through the cracks.

Nearly one in five Maine students won’t finish high school in the allotted four years, and for every student who actually drops out, there is probably another who is just filling a seat and getting by without receiving the full benefit of a quality education that comes as a result of a huge public investment.

Not every student can succeed in every environment, and that is why we have long supported the introduction of publicly funded charter schools to Maine, because they have the potential to given those students a chance to succeed outside the traditional environment.

After months of careful work in a politically charged environment, the Maine Charter School Commission has given permission to three new schools to accept students and public funds. Each is very different and each has the opportunity to help teach the state what to do and what to avoid as the charter school movement goes forward.

The Maine Academy of Natural Sciences in Hinckley, provides a model that every charter should try to emulate.

The school has an innovative educational program: A student’s day is equally divided among academic classes, community service projects and hands-on work at an on-campus farm.

The school has excellent support apart from traditional school funding. Gov. Paul LePage’s budget created funds to support living expenses for boarding students, making it a statewide program. In addition, it shares a campus with Kennebec Valley Community College, which will enrich the students’ education. All students will be required to take at least one college class before graduating, giving them a taste of what will be expected of them at the next level.

Most importantly, the school is designed to reach students who are either at risk of dropping out or are disengaged and underperforming in a traditional setting. These include students who are doing well enough to get by, but are so thoroughly bored with school that they are not getting much out of it.

If successful, the Maine Academy of Natural Sciences could be a model duplicated in other parts of the state, providing more opportunity for students to do their best. Its innovative hands-on program, outside support and commitment to students who are otherwise being failed by the school system are standards by which all charter schools should be judged.

We are less confident about the other two entries.

The Baxter Academy for Technology and Science in Portland promises to expand learning in an academic area where most agree the nation’s schools are not doing a good enough job.

The proposed school’s shaky financial backing, which led to its delaying its opening to 2013, however, suggests it may not have the outside partnership needed to make it a success.

We also are concerned that the school’s supporters seem intent on drawing only high-achieving students — “the best and the brightest” as one backer wrote in a recent letter to the editor. Those students are already successful in traditional school settings, and every school’s goal should be to challenge these students.

The top priority for the small number of new charter schools, however, should be reaching the students who are not otherwise being reached at all.

Portland has a dropout rate higher than the state average, so it seems odd that the first charter school in the city is aimed at students who already do well in school.

A criticism of the charter schools is that they are elitist, publicly funded private schools, and Baxter’s administration should avoid making that stereotype a reality.

Lastly, the Cornville elementary school looks to be just an attempt to get around the school district consolidation law. The Cornville school was closed for economic reasons when its district was forced to consolidate. The new charter school has community support, but offers little new that will reach out to underserved students.

The charter school law should not be used for this kind of end run.

Now that the first round of charter school approval is done, the commission’s report card is mixed. The Maine Academy of Natural Sciences deserves a solid grade, but the other two definitely rate incompletes.