The fiscal cliff is no longer the only threat facing the U.S. economy. Some 14,500 dockworkers from Baltimore to Texas are threatening to strike this week, a move that could throttle an array of key ports and disrupt commerce across the nation. For months, negotiations have dragged on between the dockworkers’ union and the group that represents shippers and port operators — their disagreements have centered on container royalties, which are used to augment worker wages and benefits. Without a resolution, dockworkers are poised to strike at 14 shipping-container ports starting Sunday, including Boston, New York-New ... (full story)