With the announcement by executive director Mark London that he will retire at the end of next summer, the Martha’s Vineyard Commission has been handed an opening to articulate its mission and reconsider its priorities and the time to do it right. Mr. London’s decision to step down after twelve years on the job comes as the unique regional planning agency marks its fortieth year of protecting the ecology, economy and culture of Martha’s Vineyard. Mr. London is only the sixth executive director in the commission’s history.

Much has changed in forty years since the commission was formed by an act of the state legislature and adopted by the voters of the Vineyard. Originally called the Martha’s Vineyard Land and Water Commission, its mission is in fact far broader, with unusual powers to plan and regulate a range of activities. Over the years, it has helped protect the Island against the ruinous effects of overdevelopment and carried out countless special planning initiatives across the six town boundaries that can be so fiercely parochial at times.

Mr. London came to the commission at the end of a period of turmoil following a divisive review of a luxury golf course plan for the Southern Woodlands in Oak Bluffs. His tenure coincided with a period of slower development, at least partly due to a prolonged economic recession. One of his major accomplishments was completion five years ago of the Island Plan, a fifty-year blueprint for the future for the Vineyard.

Creation of the Island Plan was no mean feat, and many of its forward-looking recommendations have been adopted. But over time, whatever authority it once held as the manifestation of the community’s collective vision for the Island has begun to slip away. Instead of serving as a vibrant, changing expression of community goals, it has become an internal planning document.

The commission, too, seems to have lost some of its mojo, its public image bruised during the recent Stop & Shop expansion review that ended abruptly last spring with no outcome. Recently two key leaders at the commission stepped down from their appointed posts, Brian Smith of West Tisbury and Ned Orleans of Tisbury. In November voters will elect nine people to serve on the 21-member commission for the next two years.

The need for a strong, central planning agency for the Island is no less critical than it was forty years ago, though the most urgent problems faced by the Vineyard have and will continue to change. Affordable housing, coastal erosion, water quality, alternative energy — these are among the crucial issues the Island will be grappling with in the years ahead, issues that really can’t be addressed by individual towns, however well meaning.

At its best, the Martha’s Vineyard Commission has been the crucible where the community’s sometimes competing values get thrashed out.

It can be the body again, but it needs to reconnect with the community, remind Islanders of why it exists and help lead public opinion once again toward a shared vision for the Island. What better time than in the context of a search for a new director.