Wal-Mart thinking twice is a prime indicator of economic upheaval. This should send shivers through local government and economic development officials about Exit 80, long seen as a linchpin for Lewiston.

It wasn’t the power of anti-sprawl activists or the failure of local salesmanship that scuttled dreams for a Wal-Mart at Exit 80 – there was none of the former, and an abundance of the latter.

Basic economics appears the real culprit. Last summer, Wal-Mart announced a steep curtailment of domestic constructions to focus – the company said – on overseas growth.

An anti-Wal-Mart group, Sprawl Busters, says the company has since scuttled construction of 45 stores, including two in Maine, Lewiston and Belfast, and let 19 others wither against stiff opposition. This has made anti-big-box activists positively gleeful.

There’s no joy about contraction in Lewiston. The city needed the economic boost of construction around Exit 80, which Wal-Mart promised to deliver, and the psychic boost of seeing an area targeted for growth finally take off.

But it’s not altogether surprising the project was called off, instead.

Construction of a second Wal-Mart in the Twin Cities always seemed superfluous, since there’s a highway running from the middle of Lewiston to the one in Auburn’s front door. In the end, basic economics ruled, which is why it seems the long-standing retail plans for Exit 80 are diverging from current economic reality.

Big-box construction overall appears to be slowing, with Wal-Mart and the recently shelved Lowe’s in Oxford as recent, tangible examples. Many national retailers have also announced plans to slow their expansion.

Meanwhile, large retail development close to Lewiston-Auburn has made the market more competitive. There are now two Targets – the oft-mentioned potential Wal-Mart replacement – within 35 minutes of L-A, for example, which should dampen hopes of construction of a third store here.

The steady retail growth in Auburn is indicative of the Twin Cities’ status as a vibrant retail market. But just as Wal-Mart’s overall announcement was a turning point in national retailing, it signals a shift in local development.

Is the boom time coming to an end?

For Exit 80 to develop as planned, another anchor retailer must believe it can succeed where Wal-Mart could not, even though Wal-Mart had just about every advantage: helpful developers and government, full regulatory approval, and a distribution hub literally in the backyard.

While a successor is possible – Wal-Mart has left the site ready for development – its exit sparks concern about Exit 80. For years, a massive retail development has been the conventional wisdom for the property.

When Wal-Mart starts thinking twice, perhaps it is no longer.