Once again, a little Maine island community has shown its stuff to the world, convincing the Maine Legislature to allow it to secede from a mainland town. Chebeague accomplished its secession from Cumberland through careful planning, sober rhetoric and lots of hard work. History may have been on the island’s side — the character of the two communities has diverged in recent years as Cumberland has developed into a Portland suburb — but Chebeague also demonstrated in a convincing way that it’s capable of managing its own affairs. Just as important, Cumberland negotiated in good faith. The deal was largely done by the time the parties got to Augusta, which is often the way these things work best. To Maine’s newest town, congratulations!