The legislative session that ended Friday was so dominated by one subject — teacher fingerprinting — that one easily could assume nothing is more important to lawmakers than protecting children from sexual predators. Imagine their surprise, then, at this Sunday headline from New Hampshire: “Sexual offenders see haven in Maine.”

The story itself, in Foster’s Daily Democrat of Dover, isn’t as quite as alarming as the headline suggests — a few, not a horde, of the Granite State’s sex offenders apparently are moving to Maine. It does, however, point out some the difficulties that can arise when states take different approaches to meeting federal mandates.

The mandate here is Megan’s Law, named for the 7-year-old New Jersey girl who was raped and murdered by neighbor no one in the community knew had two prior convictions for sexual assaults against children. The 1997 federal law required all states to keep a sex offender registry, but left it up to states to decide who had to register and how the registries are used.

Maine, of course, has a sex-offender registry law already on the books, but the 1995 statute was narrowly focused to apply only to those convicted in Maine of gross sexual assault against a child under age 16. The 1999 law designed to meet the Megan’s requirements applied to convictions in all states and it expanded considerably the range of offenses. It also applied only to those convicted on or after its Sept. 18, 1999, implementation date.

Which, though perhaps not rising to the level haven, does make it possible for some sex offenders to move here and leave their pasts behind. Not all offenders — anyone on probation or parole in another state needs permission from the Department of Corrections, and the DOC is tough in requiring that person to have a good reason for coming beyond just having a job lined up or liking the scenery. The problem is that out-of-state sex criminal who was convicted before last September and who has completed the entire sentence, including probation and parole. For that person, essentially the very person for whom Megan’s Law was designed, Megan’s Law does not apply.

It may be a loophole, but it is not an oversight. Maine lawmakers last year could have passed a law requiring the registration of all sex offenders, including those who had successfully completed the terms of parole, probation and other post-release conditions, they could have made it retroactive, in effect adding additional punishment to sentences already served. Other states did it — the problem is that many are finding their laws under attack for some very apparent civil-liberties reasons.

Maine has done a lot of things right in crafting its sexual offender laws: The information in the registry is made available to the public and provided to local law-enforcement in a responsible way that avoids generating hysteria; the 1999 law at least is on solid legal ground and should not be subject to challenge. Still, it is difficult to fathom how this Legislature could devote so much time and debate to protecting children from teachers with no record of, or propensity for, molestation and completely ignore a discrepancy between its existing law and the law of its neighboring state that produces in-migration of the worst kind.

New Hampshire police officials say several of their offenders have moved to Maine in the last year, four or five from Manchester alone, because they believed they would not have to register here. Those on parole or probation have found out otherwise, but those under no post-release conditions can truly start over. The big question, of course, is starting over at what.