Snatching defeat from the jaws of victory, the Legislature’s Transportation Committee last week took the indefensible action of indefinitely shelving a compromise plan for state-owned Sears Island. Unlike other plans, reports and studies that make their way into the hands of legislative committees, the Sears Island agreement, which took three years to come to fruition, hinged on the Transportation Committee accepting the handoff and carrying it across the goal line.

The committee’s failure to institute the agreement into state law represents more than falling short of the touchdown — it’s a fumble.

It is difficult to overstate the value of the agreement. Members of key regional environmental and land conservation groups signed on to a plan that not only allows a cargo port to be built on the island, but actually encourages the Department of Transportation to solicit a developer for the project.

The state pulled the plug on its decades long bid to build a port on the island in 1997 after fighting lawsuits from the Sierra Club. A member of the Sierra Club’s Maine chapter, as well as representatives of two area land trusts and the Penobscot Bay Alliance, helped develop the compromise plan. Having them on board with a plan that calls for a 330-acre port zone is historic.

The agreement also calls for the state to maximize shipping at nearby Mack Point on the mainland, where an industrial port has existed for more than 100 years, before seeking a port on the island. The industry representatives on the group that worked on the agreement made major concessions on this and other components of the deal, especially in setting aside 600 acres of the 931-acre island for permanent conservation.

Some of those who worked on the compromise believe behind-the-scenes treachery was at work. There is a vocal environmental group that opposes any further development of the island, even a small education center. But it is not likely that its members — who carried a mock coffin to the Transportation Committee’s meeting last week — had the ears of committee members. It’s more likely that certain transportation advocates, who walked away from the table in spring 2007 and refused to sign the agreement, want to scuttle the deal so the entire island is back in play.

But elected officials must take responsibility for their actions. The committee’s defense of its actions don’t pass the straight-faced test. Sen. Dennis Damon, D-Trenton, co-chairman of the panel, said the agreement was very much alive and would go into effect when a port is permitted. But the permitting process would ignore the agreement because it was accepted by the Transportation Committee “in principle” only, as Sen. Christine Savage, R-Union, put it.

The lines so painstakingly — and painfully — drawn on the island map delineating port and conservation would be washed away by the permitting bid. A port developer could insist on 400 acres, and all bets would be off, freeing the environmental groups to fight it tooth and nail.

Gov. John Baldacci, who wisely convened the resident stakeholder group that created the compromise plan, hopes the new Legislature will reconsider the agreement and quickly, before it unravels, enshrine it in state law. When the matter comes before the Transportation Committee again, members should have a compelling reason not to adopt it — a reason that outweighs decades of conflict and three years of consensus-building.