Why trade along America's west coast ports has ground to a halt
A nine month dispute between management companies and port workers' unions drags on, creating a gridlock for trade across the west coast. The 29 ports deal with nearly half of US maritime trade - 70 percent of America's imports are from Asia. Dozens of ships are moored, queuing off the coast waiting to unload and the costs are creeping up into hundreds of millions of dollars. President Obama is sending his labour secretary to join the negotiations, as Alastair Leithead reports from Los Angeles.