(AP) — West Coast seaports could shut down in as soon as five days — hobbling U.S. trade with Asia (and shipments to American Samoa) — if dockworkers and their employers cannot reach a new contract, the head of a maritime association warned Wednesday in remarks intended to pressure an agreement after nine months of negotiations.Operators of port terminals and shipping lines do not want to lock out longshoremen, but that would be inevitable if cargo congestion persists at ports that handle about $1 trillion in trade annually, Pacific Maritime Association CEO James McKenna said.The maritime association has been negotiating since May with the International Longshore and Warehouse Union, which represents dockworkers at 29 ports from San Diego to Seattle. For months, employers have said ports in Los Angeles/Long Beach, Oakland and Washington state are on the \brink of gridlock\ — and in recent weeks, queues of massive ships have grown longer in the waters off docks now stacked high with containers of goods.On Wednesday, McKenna said the congestion crisis has reached a tipping point, and it would make no sense to pay crews if there is no way to move cargo containers into the flow of commerce because dockside yards are too jammed.\The system can only take so much