Was the Alaska Purchase a Good Deal?

In 1867, the United States bought Alaska from Russia for $7.2 million. At the time, the acquisition was popularly dismissed as "Seward's Folly" (Seward was Secretary of State at the time), as the frozen land was considered worthless. Since that time, the conventional wisdom has been that, given Alaska's natural resources, the Alaska Purchase was a great deal (example). Economist David Barker, however, argues that the US experienced a net loss as a result of the purchase and would be better off economically if Alaska had been absorbed into Canada:

Cash flow from Alaska to the federal government since 1867 has certainly exceeded the initial purchase price, but this fact is not sufficient to demonstrate that the purchase was a sound financial investment. Using a variety of assumptions and techniques for valuing the net cash flows from Alaska, it is clear that the financial returns have not been positive. The economic benefits that have been received from Alaska over the years could have been obtained without purchasing the territory. In financial terms, Alaska has clearly been a negative net present value project for the United States.

Barker also ran similar calculations for the profitability of the US acquisition of Hawaii, the Virgin Islands, and the Gadsden Purchase.

Link via Marginal Revolution | Image: US Department of the Interior