Post-Panamax ships from Asia are already calling on the ports at Los Angeles/Long Beach, Oakland and Seattle/Tacoma, where they unload their goods, which are then taken by truck, train or plane to the east. With an expanded canal, these ships will be able to cross the isthmus and steam directly for Hampton Roads or Baltimore or New York.

K.C. Conway, author of North American Port Analysis for Colliers International, warned that competition might be too hot. In Florida, business and political leaders are campaigning to have all goods consumed in Florida enter through a Florida port.

On the East Coast, post-Panamax bragging rights go to the Port of Virginia at Norfolk, because its harbor is already dredged to the 50-foot depth needed to accommodate the deeper-draft ships.

Rodney W. Oliver, interim executive director of the Virginia Port Authority, said the canal has been critical for the growth of East Coast trade. “It will take a few years for us to reap the benefits of a wider canal,” Oliver said, “but there will be benefits for those ports that are prepared for the increase in ship size and accompanying container volumes.”

Vying to be a Mid-Atlantic hub is the port of Baltimore, which in June received four “Super-Post-Panamax” cranes built in China for $40 million, which pilots squeaked under the Chesapeake Bridge. Each of the mega-cranes has booms that can clear a 14-story building and extend 206 feet from the edge of the wharf to the opposite side of a docked ship — a reach 22 containers wide.

At the Port of Miami in Florida, authorities are boring twin $607 million tunnels that would allow big-rig trucks entering or leaving the port to bypass downtown Miami streets.

The conventional wisdom holds that the West Coast will lose market share. The ports of Los Angeles and Long Beach, which together handle about 40 percent of the nation’s imported Asian goods, could lose as much as 10 or 15 percent of their cargo business, according a group calling itself Jobs 1st Alliance, a coalition of business, government and labor leaders pushing the ports to modernize as quickly as possible.

The name of their campaign? “Beat the Canal!”

“This is going to take several years to sort out as the shipping industry experiments with new routes and hubs, but it is a very big deal, and there will be some winners and losers,” said Paul Bingham, an economist with the infrastructure consulting firm CDM Smith.

The impact of the canal may be felt far downstream. According to its June report to Congress, the Army Corps of Engineers foresees an increase in the bulk shipping of U.S. grain, fertilizer, oilseeds and petroleum, which could exploit competitive advantages provided by the improved canal, the U.S. inland waterways and post-Panamax ships.

Experts stress that the global shipping industry seeks a ruthless, penny-pinching efficiency, and routes and cargo flows will evolve.

Already, there are new ships coming into service that are so big that they won’t fit through even the expanded Panama Canal.