The U.S. economy is in the midst of its greatest peacetime expansion in history, a rare combination of low inflation and rising productivity largely credited to high-tech in general and the Internet in particular. Along with this growth, though, come real concerns that rural America is being left behind by the blistering pace of telecommunication evolution.

It is for that reason a significant part of Gov. King’s State of the State last night was not about a specific government program or proposals, but about a private-sector initiative — the extension of high-speed broadband Internet access to the small cities and towns of Maine.

Road Runner, the superfast Internet cable connection developed by Time Warner, Microsoft, Compaq and other communications/technology companies, is coming to Presque Isle and other Central Aroostook communities. Bell Atlantic is launching a major effort in DSL (digital subscriber line — the high-speed Internet service that uses existing phone lines), starting with the 16 local offices that account for about half of the company’s Maine customers.

There’s more at stake here than the convenience of no-dial connections and the ability to e-shop at speeds 200-plus times faster than the conventional modem setup. The data-rich applications used for telemedicine, education, scientific research and business increasingly require broadband. Within five years, the Internet is expected to add as much as $700 billion to gross domestic product and up to 5 million jobs. That growth will occur only where there is broadband infrastructure to support it.

Broadband disparity, a phenomena only a few years old, already is acute — some 53 million urban Americans have this cutting-edge service, compared with less than 1 million in rural areas, and the gap is expected to widen at a 20-to-1 ratio. In Maine and other rural states, this disparity not only will make business attraction difficult, it will jeopardize the continued existence of small and medium-size businesses already here.

Broadband technology is expensive to install, maintain and upgrade. In the strictly business sense, the cost of serving sparsely populated areas will not provide an acceptable return on investment. It is increasingly clear that the rural states and regions that will thrive in the future will be those in which government teams with telecommunications businesses to push this high-speed Internet technology into locales that otherwise would be left out.

The Road Runner and DSL advances, though most welcome, will at best keep the broadband gap from widening. State policy makers must sieze this opportunity and begin working with telecommunications providers to keep it moving.