Rhode Island’s unemployment rate has spiked to 8.5 percent — the highest in 15 years, and second worst in America, behind only Michigan’s, battered by the plunge of the U.S. auto industry. Meanwhile, what should be the Ocean State’s greatest potential comparative advantage, a major port at Quonset Point, goes unused.

As leaders on the Eastern Seaboard understand, ports are a vital part of a thriving economy. They create high-paying jobs, not only at the ports themselves and at spin-off companies but also at nearby businesses that have more money to hire and expand because of lower transportation costs. Shipping costs are a huge factor in where companies locate, and prosper — particularly as world trade becomes ever more important.

That is why other states blessed by nature with ocean access have port authorities, which work to expand port business and protect these vital public resources. Rhode Island, incredibly, does not.

Unlike Governor Carcieri, his predecessor, Lincoln Almond, well understood the importance of ports in a state that originally drew its wealth from the sea. He pushed to develop a containerized cargo port at Quonset Point, a superb location near the transatlantic shipping lanes. Had such a port been pursued, it might already be boosting trade throughout the Northeast and creating high-paying blue-collar jobs (and some white-collar ones, too) that Rhode Island so desperately needs.

It would be one thing for Rhode Island to snub opportunities for prosperity if it were going gang-busters in other areas. But the Ocean State’s economy is struggling woefully, thanks in large part to an unfriendly business climate, uncompetitive taxes and underperforming public schools. Even the gambling industry is suffering, and the Twin River slots palace — which produces hundreds of millions of dollars of crucial state tax revenue each year — may face bankruptcy.

When oh when will we stop wasting the tremendous potential of Quonset Point?